Still trying to figure out why i have High RPMs when I come to a stop and idle. Here's what I've checked already: Vacuum leaks, IAC, TPS, base idle screw, Spring tension, gas pedal rubbing something. I can't think of anything else. Is there a way to check if the IAC motor is sealing proerly. It seems to ork according to my Haynes Manual Test procedure, but i still think something if up with it. Here's whats happening. I drive down the street and come to a red light, The Rpms come down , but only to ~1250 to 1500 RPM. If i jab the gas, it usually comes down ~750. The idle speed for our cars is ~650, right. I was also thinking that the O2 sensor might be to blame. For a really long time i was running around on a dead cylinder and dumping the raw gas into the catylitic converter. I've since had that replaced, but have not replaced the O2 sensor. Could the ultra rich exhaust comming down the pipe screwed up the sensor without thowing a code? Now that the rich condition is fixed, could it be thinking that the exhaust is lean(as opposed to the old exhaust) and giving just that extra bit of gas to make it idle weird. This could explain the high base RPM, but not the "sticking" throttle. Any suggestions?

 

Hi
did you check that the 2 air pipes that go into the TB are the rigth way round change mind and every thing is fine now i must have put them in the wrong way when i cleaned the TB

Alex

 

well, there's only one way that mine go on. There's like this keyed sort of rubber thing that goes into the TB and it only goes in the one way, then it has the plastic piping coming off of it from there. No way for me to screw that up.

 

Replace O2 sensor. Yours is trashed. They're very sensitive, and running for some time down on a cylinder would ruin it out pretty quick. It's most likely doing just what you said...reading a false lean condition, causing the engine to compensate by dumping more fuel in. When an O2 sensor goes bad, it almost always reads as lean...not as a result of the engine thinking that the rich condition previously for you was normal operation, but as a result of the rich exhaust simply getting into the sensor element and ruining it. My O2 was on its way out and gas mileage kept getting worse and worse while I got no check engine light..replaced it and got an extra 5-8 mpg right off the bat...idled better too. Never hurts to try this..it's only $20 for a new O2 sensor, and the procedure is extremely easy.