The sensor has a variable resistance grid inside it. If a portion of the grid wears through or wears down, it could cause an intermittent signal. You need to verify that the signal getting back to the PCM is proper for the throttle position.

 

Clean your MAF Sensor. I went through all of the same issues and had the exact same systems on my 2000. Had the local Chevy dealer tell me it needed a fuel pump ($1K) before they could even check for the cause of the hiccup. Got a second opinion from a local Napa Autocare service center. They fixed it for $68. The oil from my K&N had coated the MAF Sensor with a thin coat, and it after cleaning the Blazer was back at 100%. Head down to your local auto parts store and buy a can of SENSOR SAFE cleaner. Take off the MAF (located at the air filter housing) spray the heck out of it from both sides, and wait for it to dry. Let me know, but I bet this fixes the problem.

 

My 94 is doing the same thing. Usually its fixed by a tune-up but now its caused by the tune-up. I cannot seem to figure why though. I have an AC Delco Cap and Rotor, AC Delco Double Platinum plugs and Autolite 7MM wires. I'll look more into it today by cleaning the MAF sensor and looking at the TPS.

 

^ your '94 doesn't have a MAF sensor, only a MAP sensor (which isn't cleanable).

 

on a 96 s10 4.3 4x4 blazer,how do you test the tps? there are three wires, black, blue and grey,,which is which? i probed the wires and hooked up my digi mult meter,, key on and engine off,,,,,here isthe readings i got, can anyone help memake sense of this?
greyand blue,,, 2.81 closed .35 wot
grey to black,,, 5.0closed 4.99 wot
blue to black,,, .35 closed 2.86 wot

 

Black is your ground, grey is your +5V reference from the PCM and blue should be your sensor signal back to the PCM. The values you are getting do not sound right for proper operation though. As I said, you should be around 4.5V at WOT. 2.86V is too low. Hopefully this narrows down your problem, matclark. If not, please create a new thread on it so we do not get too far off topic out of respect to the original poster in this thread.

 

well i still havent' gotten around to testing the tps. i cleaned the egr and maf sensor and still have the issue. just trying to narrow it down. hopefully ill get to test it this weekend.

 

I Checked the TPS and such just as Kylesuggested to and everything checked out to be ok. I am still having the same issues and have been unable to figure anything out???

 

You said that the prev. owner had the dist. out? This is critical because the computergets itsTDC zero from the pick up in the dist. I had that problem after an engine rebuild. The dist was installed with the gear on the camshaft out by one tooth. All of your timing both spark and injection will be retarded or advanced about 20 deg. When you put foot the computer goes "he wants power let's advance the timing" and then it runs ok. This makes me think it is late and not early. Special diagnostic tools are required to set the timing. That and you replace the dist. hold down fork with the old style adjustable model so you can turn the dist. It's about a $6 part. Even less if you can scrounge one at the wreckers.

 

I think that is very possible and am going to give that a try this weekend or as soon as i get the chance.