Rolling Idle
 

So now my poor 92 SVX has developed a bad habit of not maintaining a steady idle. It seems okay while it is cool, but once it warms up (which seems to take a while) the idle at stops is very erratic. It dips and revs like it isn't getting air or fuel or something and seems like it is about to stall. It hasn't stalled yet, but the problem seems to be getting worse so it might soon.

I recently replaced the MAF to fix a stalling problem and that seems fixed. When it had the bad MAF it would stall out at lights and corners or when I wasn't giveing it gas, which it doesn't do now. I also replaced the fuel filter thinking it could be the problem. That didn't help at all. I checked all the air hoses going into and out of the snorkus and they all seem tight (except for one on the back which will only go up about half way, but it is above the lip and there doesn't seem to be a leak so I doubt that is the problem). I also recently cleaned the throttle body. There are no check engine lights. The cars has 200,000 miles.

Any ideas what could be causing this?

PS: Also there seems to be significantly less power while the car is driving. More gas has to be applied to reach speed and the acceleration is way off. I have been beaten off the line by buses. it also seem louder.

Re: Rolling Idle
 

Sounds kinda similar to this: http://www.subaru-svx.net/forum/showthread.php?t=56866

How's your gas mileage?

Re: Rolling Idle
 

Gas Mileage? Hard to say at the moment. Prior to developing this problem it was pretty decent 19-20 mpg. I'm sure it is much lower now considering how much gas it feels like I have to give it to make it go.

I had all the spark plugs changed two years ago.

Re: Rolling Idle
 

Sort of sound like an issue I had last fall when a coil went bad on me. You may want to test if all the cylinders are firing. You can unplug the injectors as the car is idling. When you unplug one it should make the car run worse or stall. If you unplug one and it doesn't make a difference then that one is not firing and it is likely a bad coil.

Re: Rolling Idle
 

Isn't it bad to unplug injectors while the car is running?

Could it perhaps be dirty fuel injectors? I have put injector cleaner in the tank before but never actually taken the injectors off and cleaned them. Reading up on the symptoms of dirty fuel injectors in sounds promising "classic symptoms of dirty injectors, such as lean misfire, rough idle, hesitation and stumbling on light acceleration, a loss of power, and higher hydrocarbon (HC) and carbon monoxide (CO) emissions"

Is there a good guide to svx injector cleaning somewhere?

Re: Rolling Idle
 

I'm not sure, I'm just relaying a easy technique shown to me, which was very helpful in diagnosing one of my issues.

Re: Rolling Idle
 

Check plugs, injectors and another big thing to check if those turn out okay, make sure the timing hasn't jumped...

Re: Rolling Idle
 

As far as I know, these injectors arent really cleanable. If it was a major chunk of carbon built up on the outside of the tip you could scrape it off, but as far as taking the injector itself apart and cleaning it, the time involved and the chances of ruining the injector would seem to be too high to clean them.

You can have a Motorvac done on your engine (a machine with a detergent is plugged in to your fuel system and they run the engine for 15-30 minutes) Sometimes it will help, sometimes not.

you may have an exhaust restriction IE: cat plugging up
or a TPS issue, IRIS valve not opening, fuel pump dying, theres tons of things that could be going on

When you say its louder, what do you mean? its louder because you have to run the engine harder to accomplish the same speed? or the exhaust is louder (cat plugs up, causing exhaust gaskets to blow out, path of least resistance)

As far as unplugging injectors, I've done it many times on different makes/models of cars and haven't had anything negative happen from it other than car runs rough til its plugged back in. All you are doing is int erupting it long enough to see if thats the cylinder that is affected . Not like you are unplugging one and goin for a 30 mile commute to work.