When I let off the throttle it just stays at the same speed or speeds up on its own sometimes. It seems that if I punch the gas it will act fine for a while, then start acting up again. I have cleaned out my throttle body, unhooked my cruise control, checked throttle cable, and made sure that butterfly is closing when I let off gas petal (did it with engine off), also removed floor mat..just to make sure it ain't hanging up the petal. I have also hooked up my code tester and reads that everything is fine. Does anyone have any suggestions I could try next?

 

ive had the same issues with my 95 S-10 Lt 4dr 4x4

ive checked all the same things including replacing the IAC. im going to have to do a pcm relearn and see if it helps. let me know if you figure it out.

 

With the proper scan tool, you could monitor the TPS and IAC values to see if the throttle and/or IAC valve are staying open too much.

Another possibility is that you have a vacuum leak or a malfunctioning PCV valve.

 

Thanks! gunna check the pcv, my scan tool does have a option to monitor a bunch of things, will have to chek it out. Will let ya know if I figure anything out. I did look under the throttle body and it did look a little damp near a couple of the injector tube thing..my friend had a problem with his and intake was filling up with gas. Heard that is a problem on some on this design injection? Thanks for the idea's will be letting ya know what happens.

I've just checked out my IAC again and in the repair manual it says it should be 1 1/8" from flange to tip of IAC or less. Mine was about 7/8" out, adjusted it no prob yet, but will find out if works..keep ya posted. Thanks!

 

The IAC moves while you drive. Measuring it outside the truck doesn't really tell you if it is open while you are driving.

 

I replaced my PVC, used my scan tool .. it would only measure the TPS and other things but not the IAC. The TPS was closing all the way when I let off the gas, but truck still was acting like I was on the gas..(cruise still unhooked). I also sprayed sum carb cleaner around the whole top of intake and didnt seem to have any vacuum leaks. Seems to be getting worse whatever is going on, now when I punch it, it still will act up...but its weird don't do it all the time and idle fine when stopped or in drive?? Guess when breaks all the way will see what it is (haha) that seems to work sometimes too...lol

 

Start your engine and let it run for a bit. Then shut it off. Disconnect the vacuum check valve from the front of the brake booster. If you do not hear a rush of air entering the brake booster, it could be the source of your problem.

You can also fabricate a temporary EGR block off plate to eliminate that from the equation. Just get some sheet steel from Lowes or Home Depot and use some tin snips to cut it to the rough shape of the stock gasket. Then drill two holes for the mounting bolts and assemble to the intake with the EGR valve. Put a new, stock gasket between the block off plate and the manifold. If it runs better with the EGR blocked off, then the EGR valve is somehow causing the issue.

 

I tried the vacuum on the Brake booster and it is fine, I looked for my EGR valve and could not find it...so referred to my repair manual and said was in front of motor ...nothing there..?? Saw something on passenger side of motor mite be it but don't look like any EGR I've ever seen. I took sum pictures of my engine compartment don't know how to post them so gunna put them in my photo Garage if you want to check them out. But problem seems to be not acting up as much now?? Arrrr maybe just the Ghost in the machine!

 

You have a late 2002 model year truck then which does not have an EGR valve.

 

Ahh thats why I couldn't find it...Thanks swartllk for all the help tech, if I ever figure it out I will let you know...