hesitation and running issues.

steveherman · #1 07-13-2012, 08:56 PM

I am having hesitation issues.
Very random.
Worse when cold... but still there when warm.
I have replaced O2 sensors(ngk)
Spark plugs (ngk laser iridium)
Knock sensors
Coolant temp sensor (oem)
MAF (twice)
TPS (and tested to make sure it is fine and adjusted with meter)
Cam and crank sensors
Intake gaskets
Alternator (maniac)
All vacuum hoses under intake
Fuel filter AND 6 new fuel injectors.

Any one got any other ideas?
Anyone know of somewhere in central Florida I could take it and get reputable service?

Blacky · #2 07-13-2012, 09:30 PM

I would suspect one or more bad coil packs. I had similar issues and that was the culprit.

AlcyoneSVX · #3 07-14-2012, 01:31 AM

Quote:

Originally Posted by Blacky

I would suspect one or more bad coil packs. I had similar issues and that was the culprit.

Same with me.

steveherman · #4 07-14-2012, 05:12 AM

Quote:

Originally Posted by Blacky

I would suspect one or more bad coil packs. I had similar issues and that was the culprit.

is there a way to test them to see if one is the culprit and which one?

Blacky · #5 07-14-2012, 06:28 AM

With the car running and hesitation present, disconnect one at a time. If the hesitation gets worse, that one is OK. If the hesitation stays the same you've found your man. If more than one is bad you could leave the bad one disconnected and continue to pull one at a time and see if there is any change.
After I changed my plugs and one bad coil I broke down and brought it in to a local Subaru specialist. He diagnosed and replaced another bad coil with a spare I supplied.

steveherman · #6 07-14-2012, 09:25 AM

Quote:

Originally Posted by Blacky

With the car running and hesitation present, disconnect one at a time. If the hesitation gets worse, that one is OK. If the hesitation stays the same you've found your man. If more than one is bad you could leave the bad one disconnected and continue to pull one at a time and see if there is any change.
After I changed my plugs and one bad coil I broke down and brought it in to a local Subaru specialist. He diagnosed and replaced another bad coil with a spare I supplied.

too random for that.
also it is only when driving.
idle is so smooth

icingdeath88 · #7 07-14-2012, 09:51 AM

I have some spare coil packs you could use to diagnose whether one is bad.

icingdeath88 · #8 07-13-2012, 10:01 PM

Have a look at the intake right before it gets to the throttle bodies. The big plastic one. There are many nipples for large hoses to connect to. Maybe one of them is cracked and has a leak.

Another thing that comes to mind is the engine/chassis/battery grounds. Make sure they are all good and solid. You can add an engine>battery ground if you want to as well.