What is wrong with it?

[ProjectM96]

Update on rough idle problem: I still have it. I cleaned the Idle Control Valve and Throttle Body. Before reinstalling them, I checked again for vacuum leaks since I had better access to the hoses. All hoses are in good condition seem to be aging well.

I know it is not the coils or spark plugs. I know it is not the ICV/Throttle Body. I know it is not a head gasket. Mechanic says it is not a vacuum leak and I could not find a vacuum leak using various methods.

Last possible thing I can think of that causes a rough idle is the MAF sensor, but it still does not make sense because a MAF sensor is supposed to cause a CEL and I do not have a CEL light On. Plus, my scanner says no codes found. Anyways, I will try to clean it and reinstall it when I buy MAF cleaner.

Can you guys think of anything else that causes rough idle?

[jbs986]

Originally Posted by ProjectM96

Update on rough idle problem: I cleaned the Idle Control Valve and Throttle Body. Before reinstalling them, I checked again for vacuum leaks since I had better access to the hoses. All hoses are in good condition seem to be aging well.

I know it is not the coils or spark plugs. I know it is not the ICV/Throttle Body. I know it is not a head gasket. Mechanic says it is not a vacuum leak and I could not find a vacuum leak using various methods.

Last possible thing I can think of that causes a rough idle is the MAF sensor, but it still does not make sense because a MAF sensor is supposed to cause a CEL and I do not have a CEL light On. Plus, my scanner says no codes found. Anyways, I will try to clean it and reinstall it when I buy MAF cleaner.

Can you guys think of anything else that causes rough idle?

Yes my 2002 had the same problem that you are describing, it turned out to be the idler control. car runs fine now.

[ProjectM96]

No more idle problems. For now.

I guess the car needed to be driven. Cleaning the throttle body and ICV seems to have fixed the problem. I still had the problem when I started the car directly after the cleaning was finished. But once I started driving it, the problem went away.

[thom4782]

If the rough idle returns, you might consider the O2 sensors. I had a similar problem. No MAF or O2 codes, but I replaced MAF first and nothing changed. Then I replaced the O2 sensors car had 90K+ miles and they were getting tired. After driving for a few miles, the idle steadied right up and has been that way ever since.