95 Blazer throttle sticking

I am buying a 4X4 1995 Blazer from my son. He just called me from the side of the road and reported that the engine was heavily accelerating down the interstate and he couldn't pull over because he was on an on-ramp. He finally turned off the ignition and got to the side of the interstate. He started it back up....all ok. He then accelerated and it happened again. He finally got off the interstate and stopped at a gas station. I had him open the hood and operate the throttle, manually. No problem. It was smooth and no hangups. He had it towed to a repair facility and they could not replicate the problem. They told him that the cruise control COULD possibly cause the acceleration. I find this hard to believe but he says that they said that they had found some service bulletins that said it was possible.. What do you guys think??? and thanks for the input. They supposedly checked all of the usual, carbon in throttle body, worn throttle shaft, etc. Sorry for the long post.

Lynn Wagoner

Check carpet and floor mats carefully as they can make the pedal stick down, and then when moved later the problem disappears. There is also a plastic clamp on the cable above tha pedal that can be a problem if not seated correctly.

OK, thanks for the reply.

Sounds like the floormats to me.

And watch out for massive vacuum leaks. Check all hoses going to the plenum, even the ones in the back.

Update.....Son told me today that the Blazer was actually accellerating, not stuck. So, I guess it could in fact be the cruise control....that's the only thing I can think of that would accellerate the vehicle?

either the cruise was on and he kept hitting resume, the throttle butterfly is dirty and sticking, or the floormats are too thick and catching the pedal.

Update.....Son told me today that the Blazer was actually accellerating, not stuck. So, I guess it could in fact be the cruise control....that's the only thing I can think of that would accellerate the vehicle?

Is it gaining speed or just holding steady?
To rule out cruise disable it or pull pull fuse.
Any check engine lights or codes.
As said TBI sticking, gas pedal ,or floor mat, and gas linkage cable itself sticking.
They would hold steady speed .
Also if the IAC valve is coming open it can raise the engine rpm.

Update.....Son told me today that the Blazer was actually accellerating, not stuck. So, I guess it could in fact be the cruise control....that's the only thing I can think of that would accellerate the vehicle?

Vacuum leak will have it accelerating as well.

All the throttle plate essentially does is open up a big big vacuum leak.

Check ALL hoses around the upper plenum especially the brake booster.