Ok I haven't been on here in a while but I have a ? I just changed my altinator in my 3.0 cl and now when I'm I park or reverse my car revs from 1k to 3k back n forth do you guys have ne idea what it could be? I need to get it fixed before the 2nd of feb cuz I'm driving to south carolina I'm moving there. Thanks for the help!!

 

Idle Air Control Valve.

 

Either that or the TPS

 

I agree. if it was map the car would just die

 

If you were not experiencing this problem before you replaced the alternator than I would check that you used the correct alternator belt and it is properly adjusted. If this has been an on going problem than I would agree that it is probably your IACV or a vacumn leak.

 

definitely check for vacuum leak first. Did you mess with the PCV at all? All the hoses back in the intake tube? Check every hose leaving the intake manifold. Did you wash the engine before you replaced the alternator?

 

I was guessin vaccum leak also since u got work around those hoses I'm gunna have to take a look and see what I did! Thanks guys I appreciate it. And also no I didn't wash the engine b4 putting in the altinator should I have?

 

no no no.. It's best you didn't wash the engine. I ruined an IACV on a lexus by power washing the engine. It did the very same thing you are describing until I replaced it. But anyhow, when I was helping my neighbor with his prelude, we accidently broke the PCV valve off and when we started it, it revved exactly like you are describing.. up and down, up and down. Try listening close for a sucking-air sound. You could definitely hear it on his car when the PCV hose was detached.