sputtering and jerky idle
 

Hey guys, i think this is my first post, i have been here for a while but just as an onlooker. You guys are very good at helping out!! so here we go

Just about every time i run my car now, not long after a get going it starts sputtering a little. It is only noticible on low rpms. When i let it come to an idle it begins to jerk quite bad. Like the whole car shakes from the jerky idle. then once i give it gas again it continues on into a sputter. I dont know a whole lot about cars and such but i really need to get this fixed. I recently replaced the spark pulgs to see if that had something to do with it, but runs the same. Could it be the fuel filter or maybe the oxygen sensor?

Thanks very much for your help.

hmm same problem for me

started after i changed sparks

happens sometimes due to bad quality petrol... but it was not my case

u can try unplugging the injectors 1 by 1 and see if any gives different result.. i.e. if u unplug an injector and car acts better then with others u ll know thats the faulty cyllinder and u try to find whats wrong there

most likely its whole petrol system which is faulty (my case)

strill have not figured out what it is exactly....

when did it start to happen? what have u done?

if we find similar things which dont look good we can narrow our search i guess...

the other guy here with similar problem said that it turned to be fuel pump and pressure regulator... dont think it is my case as i had bad iddle for 3 months, and pump still pumping up ... so something else ...

outa curiosity, are ur vacuum hoses new? is PCV good? hose from PCV back to intake, is it good?

Sergi

Weird - my wifes car is doing the same thing. It happens each time on a cold start it runs fine and then after driving for about a mile she comes to a stop and it sputters. It feels like it is missing on one cylinder. I tested it and got the same. I put it in neutral and it still shook and sputtered. I shut it off and restarted it and it was still sputtering. Then once you get going it goes away and doesn't return.

If she lets it warm up to operating temp each morning by idleing in the driveway before she leaves it does not have the problem.

Maybe you're both visiting the same bad gas station in greenville?

Could this be a faulty temp sensor?
Have not had a check engine light yet.

ok, it just started randomly about 3-4 weeks ago. It does fine if i let it sit and warm up for a "long" while. So could it not be the oxygen sensor or the fuel filter (as i know thes have not been changed in a while). I will try the injectors and see what happens.

seems like we have come across another seemingly common problem of some sort.

my 92
 

did the same thing last Spring for about 6 weeks....
then just went away....didnt change a thing.

(even posted something about it last yr)

then 3 months later, came back for a few weeks
and then went away again....
still, only thing that was changed was fill ups at the
gas pump...

checked the plug that goes into the MAF sensor
to make sure it was in all the way....
its still running fine....If I dont get a check engine lite
Im not going to try to fix it anymore and just deal with it
for the minute or so it happens.

It also happened to mine awhile back. I guessed on it possibly being bad gas or moisture getting in there from the wet conditions we've been having. Not to difficult to do with the tank opening being positioned the way it is. I added a bottle of dry gas to clean out any water. It did the trick.

ok how it does for me:
it works fine for first couple of minutes then starts to miss. Like on the traffic light, on iddle it works fine for couple of seconds, then misses the combustion (maybe all 6 cyllinders misses 1 cycle, i dunno) and then forks fine for another few seconds. Ie revs drop down to 400-500 for a half of second or soemthing. When i accelerate from stand still, it goes really bad in the beginning, like poor acceleration and it goes slower/faster. but once its on the second gear and revs are 2500 then it goes fast.

ok i ve noticed that with 98 petrol things are not that bad at all but with 91 it s just disaster. So it depends on petrol somehow.
Also if it jerks on iddle and i press accelerator so revs go up to 5000 or something, then its find for next 10-30 seconds. Injectors were cleaned twice in last 2 month...

well maybe it is the fuel pump...but still does not loook like it...

about themp sensor. there was a post not long time ago. Dude was explaining the simptoms of bad temp sensor...


cheers
Sergi

seems like i type faster then i think....

*works fine*

:o

It has nothing to due with Octane being 91 or less.
All we can get here in Az and Ca is 91 for super unleaded
(there are a few stations with 100 octane race fuel)
But Ill I use is 91 Unical 76 and mines still intermittent
Luckily for me its been gone for a few months.

one other thing
 

I think it could be is the Mass Air Flow sensor itself
whether it be an electronic glitch, one constant we
all have though is it happens between start up
and the engine gets to operating temperature, then they
are fine for rest of the day for me.

so it is or is not possible for it to be the oxygensensor or the fuel filter??

if it was an 02 sensor it would usually throw a check engine lite AND doubt it would go away after a few minutes..

A dirty fuel filter would give you problems all the time too, it wouldnt just go away after it warmed up.
Couldnt hurt to change it though if its been over a few yrs.

I'm thinking it is sensor related. The car runs fine for a little while from a cold start - probably while it is still running in default open loop mode. Once it has run long enough to go to closed loop (but not long enough to be warmed up fully) it starts the sputtering. Once it is warmed fully it runs fine again.

I agree - probably not fuel filter or O2 sensor. Neither would make it sputter/ misfire in these conditions without other symptoms.

I can swap MAF sensors between my wifes car and mine to try to diagnose.

my idea too
 

I have an extra MAF sensor, but since my problem just went away outta the blue, I left it alone....
Let us know what you find out :) :) thanks

OH GREAT! It's an epidemic!
 

Now your all admitting your dirty little secrets! I started a thread last November about MY intermittent problem. It was fairly consistent (with rough idle for a few minutes after startup [had to be sitting for hours first], and sometimes high-speed shuddering [the car shook at speeds of 60 to 80 mph - the Dealer tried to sell me a transmission {you guys said don't diagnose AT until engine running good - glad I heeded that advice}]). The high speed shuddering was later diagnosed by me as the same engine performance problem >> When the shuddering occured on the country roads near my job, I would stop briskly >> and lo and behold >> THE SAME ROUGH IDLE!

I never really diagnosed the problem. Beav suggested cleaning the TB and AIC. I did that, but no change. I removed the Tornado air fan gizmo I'd bought off the TV ad which swirls the air just past the MAF sensor. I checked and sprayed the MAF harness (and every harness I could find, including ECU harnesses and those in the engine near ignitor and harnesses to engine wiring on right side of rear of engine (to coil wires, injectors, and sensors). I ran many continuity, voltage and ground checks on many harness terminals according to OEM shop manual>> couldn't find the problem! But, in about May, almost suddenly, the problem diminished and has been very infrequent until just recently! This must be related to some temperature thingy!! The first thing I replaced (after spark plugs and fuel filter - no change), because I thought it was temperature related, was a temperature sensor (no change), the second was oxygen sensors (on a whim! - no change). Needless to say, this has been frustrating!!! Especially, now that it is returning more often (gettting colder now here!). This is the first time I've heard that several of you have a similar problem. On the one hand, it's encouraging to be with kindred spirits. On the other hand, none of us have collectively been able to get a handle on this - How depressing! We must band together and look up!

Recently, a mechanic friend from work had an intermittent problem like this and it turned out to be a fuel pump! I got a gauge like he used, but it's hard to hook up while driving. The one time I hooked it up at home, the pressures were good >> 26 to 30 psi with the regulator functioning and 34 to 38 psi with the vacuum hose off the regulator. I need to rig the gauge so I can see the gauge thru the windshield while driving. The real test is checking this pressure while the rough idle (or shuddering) is taking place!

One time, I was able to pop off different injector connectors during this temporary (2 to 5 minutes for me) rough idle to find that one cylinder (driver rear) made no difference. AHA! I thought! But I replaced both the coil pack wire AND the injector without a change! That took a lot of the life out of me! I really thought I had it!! Then later, I popped off the injector connectors to find that ANOTHER (different - middle passenger side) didn't make a difference when removed (?).

It's dangerous to not be able to count on a good response from our SVX's when starting out in the morning (or eve). Mine also responded during this intermittent "cold" period often with a very unresponsive throttle (the car kept going, but no response for a few seconds up to a minute) even if the idle was not rough (?). I cleaned the TPS with electrical solvent as instructed here (no change), but couldn't quite bring myself to buy a TPS (or fuel pump, or MAF, or ECU for that matter)!

PLEASE DON"T GIVE UP GUYS! I THINK WE'RE CLOSE! :confused: :D :confused: :D

Waiting to hear if the maf sensor replacement works. I did run across your post from before but realized it had sort of died so i restarted it with some different words. lol guess it worked.

Hi, Im new, but i have the SAME problems in my SVX, I think I put around $700 into trying to fix it with NOTHING to show for it.

DONT SWITCH YOU MAF SENSOR OR YOUR OXYGEN SENSOR OR YOUR SPARK PLUGS, UNLESS THEY NEED REPLACEMENT FOR SURE. I SWITCHED OUT ALL THREE AND AM STILL HAVING THE SAME EXACT PROBLEM!!!!

If the same is happening to anyone else, which is this.....

when your driving, a loud whistle from the engine comes on. I go check the vacuum lines, and there are leaks ALL over the place. Im about to have ALL of them tightened to the max, and ill let you all know what happens.....

My high pitched whistle was cured when I replaced what looks like EGR tubing back into clamps on the driver's side near the middle/rear of the engine. Guess the Subaru engineers clamped them for dampening. If your problem is the same as mine you'll recognize the tubing out of it's clamps immediately.

so r we making "rough idle on svx club"??

ok guys, look. we all got similar problems but they are kinda different. for me i dont have rough idle in the morning when car is cold
3-5 mins and im there shaking in the car. when i accelerate it goes like slower faster.. weird, unpleasant

ok i ve checked tps- it was working bad, i cleaned it checked good put back, same

i drove without MAF- same
cleaned that checked that
new sparks.... (problem started after i changed em)
now im replacing ALL vacum hoses, PCV hose, and pcv itself, gonna remove manifold check it, clean it, change vacum hose under it.

so far i have not changed anything wortheble. i had oxygen sensor code before after i had PS liquid all over it, then it gone.


well if our problem depends if car is cold or hot, then i guess its not fuel pump or pressure regulator or maf or oxygen sensor

in my case it can be vacuum hoses, getting warm spread, leak somewhere.

anyone know anything about vacuum hose under the manifold?
can it be the problem?
[quote]
My high pitched whistle was cured when I replaced what looks like EGR tubing back into clamps on the driver's side near the middle/rear of the engine. Guess the Subaru engineers clamped them for dampening. If your problem is the same as mine you'll recognize the tubing out of it's clamps immediately
[quote]

what was ur problem man? symptoms? or it was not rough iddle


anyways. thx for telling what u guys done and nothing changed.
at least others wont waste time and money, and can start from something else.

anyways advise u to check all vacuum tubing, change fuel filters if they are old, run injector cleaner. maybe clean TPS and throttle body

all these does not require much money but definitly good to do.
i have vacuum diagram but unfortunately it does not say what things do and what happens if vacuum tubes got cracks
:(

anyways maybe we should open thread "coughing SVX only?" so we all can communicate there? :p

My problem is solved!!!!!
 

Hey...i had ALLLLLL of these symptoms, but guess what......i bought the car 2 months ago from some fumb teenager that didnt know what he was doing. Turns out that all the whistling was coming fron the intake manifold...i checked it only to see that nthe bolts were loose as hell.....i could of unscrewed them with my fingers!!!! all the air was leaking from the loose intake manifold!! so i tightened it up all the way and now my car is PERFECT!!!!! nothing is wrong with it now!!!! EVERYONE CHECK TO SEE IF IT IS ON THERE TIGHT...YOU MIGHT HAVE THE SAME PROBLEM!!!! GOOD LUCK GUYS!!! IM SO HAPPPYYYYYYY:D :D

lols

geez, no offence man, but u look like happy little kid... hehe

see, problem is that things are way more complicated with SVX then just lose bolts... but yes its good idea to spend couple of hours every half year and check all bolts u can find... transmition oil tank bolts and engine oil tank bolts tend to get lose...and oil leaks there...

but anyways anyone with good knowledge here who can help us?

pls :confused:

ok i think that in general the problem is the same as far as time because mine doenst do it time i crank it, it is after i have driven a minute or two, i think that is what everybody has said. So the problem is the exact same. Dont know anything abou this whistling though, never had that problem.

oh ok i just thought u guys have problems when car is cold...

anyways have u checked all ur vacuum hoses? are they flexible and look new? i ve changed 1 so far, to regulator, things became bit better

got few other which went bad


im just trying to find what we all have in common, coz i doubt it ll be fuel pump as they dont break that often and problem is common.


anyways i did the other thing today: there is a screw which controls the idle opening of throttle batterflies. unscrewed that abit and opened the batterflies abit...seems like things became abit better
still tasting...

rmps are same, but when it drops rpms on idle, it does not shake that bad now, just abit

Rough Idle
 

ok now i put some stuff in my locker:

vacuum diagram for SVX (ur rough idle can be caused by 1 of those hoses having a crack)

plus i put lotsa stuff for trouble shooting
checking sensors and all that
its all the subaru manuals which someone gave the link few months ago, but i dunno if it is still on the web.

anyways i put some stuff for troubleshooting in my locker

so:
vacuum diagram:

relevent trouble shooting:

refere to a diagram, it has a rough idle and stalling as trouble, and suggestions for troubleshooting
unfortunately i could not find "ECU power"
anywyas have a look and have fun troubleshooting


+ some more in my locker

hope its gonna help u guys somehow. just i dont have time now reading all that and trying to c whats wrong, i got exams in uni.

A friends SVX had a simiar issue. This was so simple:

- Restore 6 cylinder engine oil treatment to improve compression (change oil in 1500 miles, use restore with 10W-30, then go to 10W-40 after for a smooth transition)

- Restore Fuel System cleaner and octane booster (use with octane closest to 91, not garbage quality gas)

Lots of rough running until gas was out of tank. Next Citgo 93 octane fill up: smooth as a new Lexus.

Now every oil change, I use the Restore Fuel System cleaner because of her results. Can't hurt.

Once, I even tried this Oxygen Sensor cleaner when I got my SVX, just for preventitive maintainance. Didn't do anything, but still makes me feel better knowing my oxygen sensors are maybe a little bit cleaner. Be careful not to wait to put it in the gas tank. I did, and in about a minute the bottle was noticably lighter than when I put it down. After I put it in, it took only a few seconds before the bottle was dry as a whistle.

Not saying this will solve all your problems, but it definitely should solve some.

Not to tell everyone that I have THE SOLUTION, and I've never had the problem as described by all of you with my SVX, but DID have the identical symptoms with my '88 Voyager van a few months ago. I took the cheap route first, & thoroughly cleaned out the throttle body "butterfly" area with plain old carburator cleaner spray. It was REALLY dirty. I sprayed the intake generously while running the engine & goosing the throttle. I also poured Techron cleaner in the gas tank. After this ten dollar tune-up, I took her out & drove her hard for a few miles.
Since then the old 170K plus van runs like new.
Who knows? - it's worth a try.

Ron (Mopar master mechanic).

ok i had injector cleaner (twice) i had oil changed, i had that oil flush of course, im running 20th tank of fuel, i cleaned throttle body and it was not dirty AT ALL, i cleaned TPS (it did not work properly), but does now. nothing helped

all my problems started when i changed sparks... all of them, before that SVX was perfect even with its 270,000kms
well seems like i overestimated myself and went under the bonnet when i should not ...
anyways too late too bad

are u guys advising some special oil flushs and incjector cleaners?

maybe mine were not good?.. i dunno.... also seems like i ve done my tune up and it did not help..

also the only thing which helped abit, is that i played with that idle screw (butterflies are opened abit on iddle now) and car goes better then it did before, smoother but it ofcourse did not solve the whole problem, but smoothed it so things aint that bad for me now...

gonna disconnect battery for 20 mins tomorrow to reset the memory of computer.

anyways keep each other informing of the actions, might help, eventually to solve the problem

i *think* theres a diff between fuel injector and fuel system cleaners. is that true?

TREAT THIS!
 

I just put TECHRON Fuel System Cleaner (20 oz., $9.95) into my gas tank. I'll let you know if it helps. As I said, I'm starting to get the intermittent rough idle (on startup) for a few minutes again! :confused: :D

well i started to get bad millage now:confused:
even before i opened the batterflies abit on iddle

so far it takes 15 liters per 100km (dunno in mpg)

the openning batterflies helped the car dont shake on iddle, but still rough iddle

also if i drive on highway up to small hill, and revs are 1800-1900 (speed 80-100kms) i get missing combastion which is like 1 missing in few seconds... weird

what are the symptoms of bad fuel pump?

we have got to figure this out people, it feels like my car is gonna die from the rough idle

Well, SVXs mileage varies hugely with how you drive. With me, pure city is 14 MPG, pure highway is 24, and I usually wind up getting 19. But I have a heavy foot. Does anyone know how to convert his figures to MPG?

Yup. Here's my math:

15L / 100km

15L/3.78 = 3.968 Gal
100km*.6213 = 62.13 miles

3.968 Gal / 62.13 miles
1 Gal / 15.658 miles

15.658 MPG

TECHRON fuel system cleaner
 

No change in performance [intermittent rough idle] after this cleaner used. Now I put in some octane booster>> No change so far! :confused:

Re: TECHRON fuel system cleaner
 

I hate techron. never did anything for my cars. get restore.

ZOOOOOOOOM!!!!!
 

Seems like I get a little more power with the octane booster! Have to race my wife (we go off at stop signs often) soon to really tell. :D

Looks like I get to join this merry group too



About 3 weeks ago, I was sitting in the car waiting for Cass and was watching the rpm's (had always been fascinated with how smooth and constant they were) - anyways, the rpm's begin to drop and I notice the car begin to rock..."I say, I wonder what that is" says I (note: much more colourful language used, and to remain used for the rest of this topic in addition to hair pulling :eek:

In 'N' I apply more rpm to see what it does and I notice that the smooth engine note has what appears to be a miss or something our of synch...at about 1500rpm to 1700rpm the car begins to chug and die!!:eek: All manners aside, I cry "what the fire truck is going on"

Has been doing that now at that rpm speed, which is a pain when in 'D' and driving, then going to accelerate and the engine and transmission (clunky changes) have a meeting, decide on a course of action (meanwhile, I am facing oncoming traffic!) then decide, as I press the accelerator furiously, to unleash all the power at once and whhhhhhhhhhhhhhhhhhheeeeeeeeeey off it screams down the road, transmission slamming back a gear or too, Cassie belting me into the head and me protesting "Its the car"

I have no &^*^ idea...will try changing air filter, fuel additives then driving off a cliff

IDLE SCHMIDDLE!
 

Since your twist on the no guts/rough idle syndrome occurs at a specific RPM range, maybe a Throttle Position Sensor clean job is in order. If interested, do a search on TPS cleaning (I think Trevor or other common poster). Involves removing TPS, then squirting electronics aerosol spray solvent into small hole in TPS (while rotating sensor shaft back and forth) to clean electronic "rheostat" inside. Pretty easy to do!

Good Luck :D

P.S. Have you cleaned your throttle body and AIC? A little harder to do, but highly recommended by many here for a plethora of ailments!