I t idles up and down slightly while in park. I changed the fuel filter plugs air filter iac motor ran injector cleaner through it and ran a computer on it . I got no check engine light. I've checked out every thing that deals with air intake and I'm finding that everything seems to work properly.

 

A vacuum leak would be the first thing that comes to mind. I would connect a scan tool where you can actually check for codes and see what the fuel trims are at. Fuel trims would tell you right away if air is being drawn in from a leak. Also, did you clean the entire throttle body when you changed the IAC? If not, you should take the throttle body off and do a good cleaning along with a new gasket.

 

I cleaned the throttle body. I ran the computer but no codes and also checked fuel pressure and that's on spot. What did you mean by fuel trim cause maybe I'm missing something I should be doing. I don't hear a vacuum leak but I probably need to do a more thorough check on them tho.thank you for the info

 

Fuel trims can be obtained with a scan tool capable of displaying live data. Long and short term fuel trims show a rich or lean condition by indicating whether the computer is adding or lessening fuel to the mix to compensate for a condition the engine is encountering. A perfect reading would be zero(perfect is not likely). High trims on the positive side indicate a lean condition while negative readings indicate a rich condition. +/- 5 from zero generally is acceptable.A vacuum leak would be indicated by a highly negative reading.

 

thank you very much I'll try it