Idle Problems!

Ive had a Idle problem with my 99VX for about a year now. The isuzu dealer was no help buy my local mechanic was able to shine some light on it. My engine will idle around 2800 RPM's, and as you know changing from drive to park and so on sounds like the transmission is about to fall out. My mechanic found out that if you take off the neg. cable on the battery for over 10 min. the problem goes away and it idles down. This seems to work for about a week and then it slowly starts to rise again. My mechanic tells me that the computer is going bad and that it thinks it is in a very cold place...but in reality its in Tennessee! Can anyone help me out?? :confused:

Thanks...

I doubt it's the computer...if you search this site for "idle" you will find many of the causes, the most likely being cracked intake gaskets although a dirty idle control valve would be the first thing to look at. Any codes being thrown as they would be VERY helpful but not all problems cause them to be shown. Resetting the ECU and having the problem come back does not indicate the ECU is bad.

I would of said ECU like the mechanic. but the other suggestions are possibilities. When you take the battery cable off, that resets the ECU which in turn erases ECU memory. So unless you leaving something out, then I would personally point to the ECU. But I am no Mechanic.

i had a similar problem with a ford escort. it was the mass air flow sensor . the check engine light would never come on and there would be no codes. when it does it unplug your maf sensor and see if it gets better. shawn

Good idea. I forgot about that option.

Idle control valve....

I had the same problem at around 50k miles......I would start the engine and it would immediately die (intermittent at first, but getting worse); or, decelerating to a stop, then dead....it would recover after several restarts

I had the idle control valve replaced (cleaning didnt seem to work permanently) and it hasnt happened since....after about another 100k miles