Driving me !! I replaced the valve cover gaskets today, so I replaced the plugs, wires and swapped out the IAC with another known working one.. I still have a low idle issue when the engine is hot.
In Park/Neutral is idles at 650rpm and in gear it idles at 500, shaking and growing. I cleaned the throttle bodies and now I just don't know what to check. There are no fault codes. Any known issues for first gen 3.5s?
check pcv valve system also check air filter.Also the throttle position sensor could be dirty.There could also be a vacuum leak
Air filter is good. I don't think there are any vacuum leaks as I just put all the vacuum lines back and the fuel rail o-ring recall was just done, so I know all the seals and gaskets are new from the plenum upwards. I'll recheck. PCV hoses are new, but I'll check the rest. TPS was a thought - I'll clean it or swap it out.
Thanks for the ideas. I think some of which I take for granted are fine. ;) I'll check it out.
The EGR valve itself works all right. I did have to replace the transducer solenoid though not too long ago as it was leaving fault codes. This issue with low idle has existed since I bought the car and there are no current fault codes.
I couldn't find any reason for the low idle when hot, other than the throttle body adjustments. I noticed on the throttle bodies, someone has removed the plugs for the adjustment, so I figure some moron along the way was fudging around with it. So it's adjusted and idles at about 575rpm in gear now, which is a huge improvement. Next spring I will refine it more. The car is parked now for the winter.