I seem to be having some problems with my throttle body. Whenever the car first reaches operating temperature, the idle speed will drop down to 500-600 rpms in gear. If I continue to drive it, the idle speed will come up to 750-800 rpms in gear. I'm guessing the idle speed comes up after the throttle body heats up to the engine temperature.

That really isn't a big deal. Here's my main problem.

Sometimes after driving the vehicle for a while, I will stop somewhere and put the truck park. When I do this the truck will idle really high. Somewhere between 1300-1500 rpms. Whenever it does this, I can rev the motor up above 3000 and then the idle will return back to normal.

My guess is that something is sticking inside the throttle body. I know that the first thing that everyone is going to say is to clean the throttle body. The only problem is that I have done this already. It is very clean inside my TB. My toothbrush wasn't black anymore when I was done with the cleaning.

My TPS is also new.

If anyone has any ideas would you please help me.

Thanks

 

IACV - Idle Air Control Valve maybe?

 

You could try putting a stronger throttle return spring on.That would be an inexpensive solution.Also shoot the throttle linkage with a good lubricate.

 

It sounds like your dashpot on the t-body is sticking. The dashpot is the doohicky that prevents the throttle valve from shuttling too quickly when you let off the gas. It basically acts like a shock absorber.

 

Do we have dashpot's on our 3.0L? I only thought they came on the 4-cyl...a la 22r and 22re, etc.

 

I'm pretty sure they come on the 3.0L as well. Whoops, just read his sig and he's got an auto so it won't have one.

 

OK, so only rigs with manual tranny's have them, huh? Thanks for the info.

 

Here is some new info on my idle problem.

I drove the truck today and let everything thoroughly warm up. I turned it off for a few minutes. I then started the truck up and slowly pushed on the gas pedal. Upon letting off the gas pedal, my rpms stayed up anywhere between 1250 to almost 2k one time. I found that tapping on top of the throttle body with a screwdriver caused the idle to come back down. I watched the throttle linkage attached to the butterfly when doing this and noticed that the butterfly did not move at all. This tells me that something inside or attached to the throttle body is becoming stuck.

Any ideas as to what could be going on?

Thanks.

 

Have you checked to see if there are small screws on the butterfly that "may" be loose?? (I am not even positive it has them) Try some PB blaster where the butterfly shaft goes thru the TB.. It may stll be sticking a hair, It don't take much at idle..

My other thought would be that "dash pot" that is vaccume operated.. Is the vaccume source good (like a cracked hose??)

 

I've looked all over my engine compartment and haven't found any vacuum leaks yet. I can't seem to hear any leaks.

I have sprayed all my TB linkage down with silicone lubricant. I did this just the other day when I cleaned my TB for a second time. I even put a small shot of it on both sides of the butterfly just to make sure everything was loose. I may try lubricating everything again.

Where is this "dash pot" thing you are talking about? Is there some way that I can test it?

Thanks.