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Still rough idle...

Changed the MAF, the ICV, the intake boot, the spark plugs, the air filter, checked the whole intake for air leaks, the idle is still uneven. Even worse than before as it occured only when the engine was cold (the engine ran very well and smooth once warmed up), now it is rough all the time (more when cold though)...

Any idea? In general, what can affect the idle when the engine is cold?

Thanks in advance.

1. Are your symptoms accompanied by an SES light or corresponding code?
2. What type of spark plugs did you replace with?
3. Have you removed the Idle Control Valve and Throttle Body and cleaned both?

4. Is the idle surging (e.g. rpms jumping up and down) while neutral or in park? Is it also surging while driving?

Quote:

Originally Posted by Wayne's World (Post 670798)

1. Are your symptoms accompanied by an SES light or corresponding code? Yes, the Peake tool displays all the codes concerned by a wrong mixture so related to O2 sensors measures (E3, E4, F3, etc, and also the cat codes, CA, ...), not surprising as the mixture is not correct. No other codes apart these ones.
2. What type of spark plugs did you replace with? The original ones, NGK platinium
3. Have you removed the Idle Control Valve and Throttle Body and cleaned both? ICV just replaced by a brand new one, throttle body not cleaned yet.
4. Is the idle surging (e.g. rpms jumping up and down) while neutral or in park? Is it also surging while driving?The idle is rough but not really jumping. The engine starts easily, the idle goes to 1000 rpm then drop to 500 and the misfires begin, then the engine can stall if I don't blip the pedal. On the other hand the idle can jump up and down while just accelerating to say 1200 rpm (engine cold), in this case it jumps from 1200 to 500 and so on. Once the engine is hot, the idle is better although it begin to be rough again and the SES light comes on if I let the engine idling for more than 15 seconds.
Thanks for the help..

Quote:

Originally Posted by sfcl (Post 670814)

you have a bad crankcase vent valve.