You guys have never let me down before so here we go. I'm working on a 1996 S-10 Blazer with a 4.3 V-6 54000 miles. When started cold (20-40 degrees) it stumbles at idle and dies then I start it back up it runs up between 2500 and 3500 rpm until you shut it off. Once it warms up its fine. I've replaced the throttle position sensor no dice. Any ideas would be welcomed. Thanks Barry

 

Have you checked for vaccume lines that are lose? I had something similar to this on a 305 engine, a line had come off near the throttle body.

Just grasping at straws...

 

Might also try the idle speed servo..seems like I had a problem like this with my old blazer and the servo had bad carbon buildup on it. I just took it out and wiped it off with a paper towel, put it back in and problem solved.

 

ditto on the IACV

 

Thanks guys! I knew I could count on the DTR bunch!

 

Good advice above. I would also spray some water or carb cleaner around the sides of the intake manifold (engine running) to look for a vacuum leak at the intake gaskets.

 

Is it a 4.3-L with C.M.P.F.I.(central. multi, point, fuel, injection) or is a throttle body setup.
If it`s a CMPFI, it sounds like the plenum gasket(common) has a vacuum leak.
Also check the PCV and M.A.P. sensor hose at the back of the plenum next to the distributor. If it`s a TBI unit. Check the TBI base gasket(common) for a vacuum leak. Also make sure the PCV hose is connected.
It sounds like you have a gross vacuum leak to me.
Run the engine and listen for the hissing/sucking sound that`s not normal and see if you can trace it to the source. Happy hunting...

 

I had that problem before and found the trottle body to be dirty had it cleaned and all was good again.

 

I had a 1998 Jimmy that did the same stinkin' thing. it progessively got worse until it came to a point where i had to stick a torpedo heater under it to start it when it was cold.. Ended up being the computer module. I sold that piece of junk. I hated that thing and it was THE WORST vehicle i ever had. 2 tranny's, ate rotors all the time, complete exhaust from the manifold back replaced.. criuse control broke speedo broke... all this and it didn't even have 100,000 on it!!! Sell it and run while you still can !!!

 

Hey now! We have had two Blazers (my wifes ride) a 95 that we sold at 200k and a 01 that has 92k trouble free miles! The only thing I had to do to the 95 was replace the water pump, and we had a vaccum line come loose (similar to the above scenario) all in all other than maintenance I had all of $75 in repairs. She uses them for a daily commuting vehicle, but they do some work on the farm too. These are great little all around rigs!

 

Don't forget the alternators, oil cooler lines, and intake gaskets. They're not my favorite either. When one comes into the shop, we know it's gonna be in there for a few days.

 

Thanks again guys. Don't forget about replacing the head gaskets at around 40000 miles because the anti freeze GM put in them around 96 ate up the gasket.

 

Ok, how about some info on a '93 4.3 vortec auto 4wd? The PCM is the only thing left I can think of. Shut off on me on the road, no spitting or sputtering. It was down about 2 quarts of oil. Didn't say it was overheated, yet a trickle was going into the overflow. Put oil in and wouldn't start. Unplugged the battery and reconnected after sitting over night and no-go. Replaced the ignition module in the distributer, and fuel filter. Fuel pump comes on and build pressure. I cracked the line at the filter after installing the new one and it not starting, and had line pressure. I have a TPS to put on, but wanted to wait to commit to buying it, I thought it only control fueling while the vehicle was running. I take the intake off and spray fuel into the air plenum and it starts up and will run if I keep spraying fuel in.

Patientlywaitingwithwhiteknucklesandgrittingteethd on