About six months ago I started having a high idle problem. I can't pinpoint what exactly causes it because it is so unpredictable. When it does stick, it usually sticks at 2000 RPM until I come to a complete stop, then it drops back down to normal. Occasionally it will idle up to 2500, and I've noticed something new, it will act in the exact opposite...I step on the gas and nothing happens until I let off and hit it again. First I cleaned the IAC, that helped for a few weeks. Then I replaced the IAC, that helped for a few months. Now I'm starting to think that maybe it might be the TPS. Can the TPS cause these symptoms? Or am I looking at something different?

 

I have the same truck.... Just to add, I get a high rev when I start it up in the morning for about 2 seconds and than the idle drops back down to normal... seems to do it only when the truck is cold.

I'm not sure what the problem is either.

 

The high rev you are experiencing is perfectly normal. There was a post about that much earlier and it seems most engines do that high rev on a cold start up. Mine does it whenever it feels like it, but I've noticed mainly after heavy accleration, or cruising at very low RPM when stuck behind a slow driver. Just remembered that part...

 

Have you checked the linkage, it could be sticking and not returning to idle position?
Dave

 

Are you using a K&N air filter? The oil and dirt from a K&N air filter can contaminate MAF sensors, and gum up IAC valves. This would explain why cleaning, then replacing your IAC valve helped your idle problem. K&N has recently come out with a "precharger" filter to use with their regular
filter in dusty conditions. This will reduce the amount of dirt being passed by the regular K&N filter.

 

I do use a K&N filter, but it was doing this before I switched to that, so I think it may be something else. I'll have to look in to that precharger.

 

The OEM paper air filter will solve your IAC problems also.

 

Does anyone make a paper 3" conical filter? If they did I would probably switch to that. I love the minor power increase and major sound difference I get with my conical. Find me a paper conical and I'll switch to it.