rough idle

[busyb187]

Hello everyone. Well I have a 97 eclipse get. It has been giving me trouble lately. It idles rough,and it was giving men trouble codes p0304 and p0135. I replaced spark plugs, spark plug wires, and oxygen sensor. Check engine light went away but rough idle is still there. I have no idea what else to check. Any ideas or suggestions? Any one had a similar problem and found a fix? Thanks in advance.

 

[92AWDHX40]

Dsm Idle Problem!!! - Car Forums and Automotive Chat


Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html



these may help you get started.

 

[GSTurbo1]

compression check then boost leak check

 

[shavers55]

Check your IAC or ISC as some people call them. It might be super dirty with carbon deposits. Mine used to do the same thing till i cleaned it off with some carburetor cleaner and a rag. Its located on your TB(throttle body) if you dont know

 

[Chicken Patty]

Rough idle I'd lean more towards boost leak/compression. But never bad to check other things. Injector seals/o-rings could be bad, but if the seals are bad, you'll find out in a boost leak test.

 

[Aphix]

I agree on a BLT, injector seals are almost certainly leaking if you they havent been replaced. I would also check your TB shaft seals as those are very common. The ISC module will not throw an CEL as well because it's a step motor, so you will need to check the impedance to ensure its working properly (another likely issue).

If you have a reliable boost gauge then check your In. Hg at vacuum is at or close to 20. Anything less than that is indicative of a vacuum leak between the intake runners and the TB plate. (injectors seals, intake gasket, TB shaft seals, TB gaskets).