epagidas

My 92' Chevy S10 4x2 pickup 4.3L V6 auto trans has 185,000 miles and has been giving me the following problem. It started about a month ago and has gotten worse, at first when I would coast to a stop or be at a light it would stall on me as if someone turned the key off. I would put it in Park and it would start up right away and then sometimes do it again or not the rest of the day. The next few times it got worse and took longer to get it started but it would start and I could keep it going at a light if I kept on the throttle a little. Now if I warm up the truck from a cold start and just leave it there for about five minutes it stalls on me and I have to wait a long time for it to cool down before it can start up again. Any ideas on what it can be? Here is what I have done so far.

Tune up new plugs, wires, cap, rotor, pcv valve
Cleaned TBI
new fuel filter
new fuel pressure regulator/diaphragm
new sending unit
new fuel pump
new TPS (throttle position sender)

I also just disconnected the TCC on the transmission and it still did the same thing.

Again the truck runs fine when it starts up and also runs like a brand new truck on the highway at cruising speed. Only when I let off the gas and come to an idle does it stall on me.

Thanks for your help.

golfer

just a guess .... Could be the crank sensor

shawnvw

If you can get the truck running long enough to check....see if there is vacuum at the PCV valve. these TBI unit are known for beinging plugged up solid throughout the vacuum ports. if there is no vacuum, remove the throttle body, and give a really good cleaning using a good air intake cleaner, wire brush, and some compressed air. make sure you put a new gasket underneath it when re-installing. And while your there, give the IAC Motor a good cleaning

golfer

Good point shawn.

epagidas

I haven't had a chance to check for vacuum yet. Today I started it up and drove six blocks and stopped at a light and it stalled on me. This time it wouldn't start, I even came back to it 45 minutes later and it wouldn't start. I sprayed very little starter fluid and she fired right up but stalled once I let up on the pedal. I tried it again with starter fluid and started right up again and held the pedal for about a minute this time and I was able to get it back home. Once I got home I let it idle for about ten minutes no problem. I revved it up and let it idle and she stalled again. Any thoughts on what is happening now? Can it still be related to the vacuum you mentioned? How do I check for vacuum at the PCV valve?
Sorry for the dumb questions but I'm a backyard mechanic.

Thanks,
Steve

shawnvw

could be an issue with fuel pressure or dirty injectors. Its very possible that the airways could be plugged like i was saying earlier, which explains why it won't run unless you open the butterfly. With the engine running, pull the pcv valve out of the valve cover, and put your finger on the bottom, there should be good vacuum there. If there is little to none, then you need to remove the throttle body and clean it out.

epagidas

Shawn,

I tried to start it up to test the pcv and it wouldn't start, just turned over. So I was going to squirt some starting fluid in there to get her going. I took the air cleaner cover off and before I sprayed the fluid I decided to try to start it one more time. Except this time I pulled the pcv out of the valve cover to be ready to test. Weird thing is it started right up where as a minute ago it wouldn't start and the only thing I did was pull the pcv and take air cleaner cover off. Anyway I checked for vacuum and it has real good vacuum, my skin was getting pulled into the pcv and it sounded like it dropped a little in rpms. I would remove my finger and the rpms would rise again. I did this a few times and it was always the same. I then shutdown and restarted numerous times no problem.

This is one of those strange problems. One person on another site suggested the computer might be bad, I would hate to try that without knowing for sure. Any ideas on what to try next?

Thanks again,
Steve

shawnvw

your air filter wouldn't be totally plugged up would it?...you said you pulled the breather hose off and it started right up.

Theoretically it could be the computer........... fuel pump, wiring, injectors, crank sensor, ign module, cap rotor wires....anything.

Seein as though you have replace almost everything already, you may want to take it to a shop so they can dig a little deeper into it before you spend a bunch of money on a new computer

AlohaJMW

Did you figure it out yet? Had the same problem with my extreme. Let me know.

AlohaJMW

Did you figure it out yet? Had the same problem with my Extreme a few months ago. Let me know.