I've read every "high idle" thread... still have a

[A-man930]

'90 renix 4.0L. Idle's between 1600 and 1900 after it warms up. At cold start its around 1K. this makes me think its not a vaccum leak, otherwise wouldn't it start out high? I'm going to try and tighten the intake bolts and check as many lines as I can with a propane torch this weekend. Is my IAC valve bad? I did a check on it a while ago and it was fine (I'll have to look up what exactly the test consisted of later, it was in the Hayne's manual...) Any thoughts?

[A-man930]

No help?

[Twisty]

I'd try the IAC or TPS.

[Oizarod115]

adjust your throttle position sensor, the TPS

 

should be about .83 or near there. if it cannot be adjusted in that range it needs to be replaced.

 

this site will tell you how to do it. he says .8v so do that

http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

[A-man930]

I was able to get about 4 intake bolts significantly tighter and the idle has dropped to about 1450. I'm assuming that there's either another vaccum leak somewhere or the intake still isn't sealed up all the way. Either way its much less anoying.

As far as my question as to why it doesn't idle high at start-up I think I've figured it out. At start-up the computer is in open loop mode correct? (preset fuel and spark tables, no imput from the MAP, TPS, O2, etc...) Once everyting's warmed up the MAP detects the vaccum leak (same result as having the throttle open) and the computer adjusts the fuel accordingly. I guess the TPS imput is ignored over the MAP. Does this sound in the ballpark?