Idealing Question

[bigboy]

Ok my truck is doing something funny. It ideals high until it warms up. Then it will ideal down then up and then down again. But after a while it will ideal like it is supposed to. Then it will start doing it again after running for about 10 minutes. Earlier it died on me a few times. I'm thinking it is the Ideal air control valve myself. I have a 91 s10 with a 4.3 TBI and I was wondering if I could use that IACV off of it. The s10 is a project I started a while back and decided to scrap it.

Oh the truck is a 93 with a 5.7 TBI.

 

[Sepiroth]

Check for any vacuum leaks in or around the intake and throttle body, like the throttle body gasket. Usually a surge in idle is caused by a vacuum leak. Also check your maf/map sensor.

 

[bigboy]

Good point I'll check those things today. But if it's not either one of those then I will try the IACV.

 

[Sepiroth]

Use carb cleaner spray. If there is a vacuum leak, when using the spray, you will get a definite surge in idle when it hits the source.

 

[bigboy]

I went and got the map sensor of my s10. I'm pretty sure that is the problem and now it just idles high. So I'm gonna check the timing on it soon. I tried the carb cleaner trick and nothing.

 

[bigboy]

Well I figured out the high idle problem today. It was the TPS and timing.

 

[bigboy]

Here is my issue right now. The truck idles high sometimes like around 1500-1700 rpms when you start it up and will not idle down. When it does that it shifts like it has a shift kit in it. And when you pull up somewhere most of the time when you put it in neutral or park it will idle high. But other times it idles around 700-900 rpms and it will shift like it is supposed too. I have a list of codes I just pulled from the truck. I'm leaning towards a bad TPS and maybe an O2 sensor. I'm probably gonna go ahead and replace the O2 soon because MPG is sucking right now. I have replaced the TPS a few times already but I got the cheaper one. Would you recommend going with an ACDelco? I have looked for vacuum leaks and can not find any, so I'm ruling that out as a possible culprit.

Here is the list of codes that I pulled this morning.
13
22
32
67
82

I'm almost certain that the TPS is what is causing 67 & 82 codes to show up, because the solenoid for 1-2 has been replaced earlier this year when I had the transmission rebuilt.

So if anybody could lend me an opinion on this issue I would appreciate it.