When I come to a complete stop and try to take off my 2001 chevy blazer engine wants to stall when it is hot in stop and go traffic. It only happens in hot weather.

 

I have this very same thing going on but only intermittently. Can't predict it or make it happen. It seems like the outside temp has to be over 100F. An experienced GM mechanic changed the throttle position sensor. He had a reasonable explanation for that. Two days ago it happened again right in downtown Las Vegas. That was a little scary. It always starts right up again and runs just fine until some stop light again down the road.

Mine is an 02 with 98K miles.

I don't mind fixing things if I just knew what was broken.

 

Problems like this are often quite difficult to diagnose because the fault may only exist at a given set of conditions. If the engine starts right back up, then that makes it even more difficult to test for.

The heat could be affecting the ICM (ignition control module). The ICM is mounted to a heat sink and should have good thermal paste between it and the heat sink. If the thermal paste is dried out or just not there, it cannot effectively cool itself. You used to be able to remove the coil & ICM and have them tested at most autoparts stores, but they have become few & far between. THIS SITE runs through the testing of both.

 

I learned a little more on Fri. Made a test run in the high heat (108 - 113) of about 60 miles round trip. Near the end I could make it stumble at high speeds too, 70mph. I'd hit the gas and after about 2 secs it stumbled. Didn't die due to my momentum I suspect. Only happens when accelerating so it has something to do with demanding more fuel. I'm starting to wonder about the fuel pump. I've had one fail similar to that years ago. It's not noisy at all. Could it be an injector nozzle? Most of the electronics in there doesn't know if there's a demand for power or not. Or...am I wrong about that???

 

The ignition switch could also be something to check out. Those like to act funny when they get hot. But I've never heard of them causing problems like you are having, I do know they cause stalling tho. Swartlkk will probably know weather or not the ignition switch Could cause this.

 

My 2002 Blazer is doing the same thing when outside temperatures are at 100+ temperatures; stalling at a stop light and restarting easily. It only seems to do this intermittently some days and then on others nearly every time pulling away from a stop in traffic. The engine has 115,000 miles. All maintenance has been done on schedule since new.

 

I think I have it fixed here (fingers still crossed). The dealer replaced the injectors. Very expensive! There are 6 in there in a cluster with fingers shooting the fuel into the intake runners. I've been flogging it in the high heat for a couple days now and no failure yet. It also seems to run a little quieter and smoother than before. Just my gut feel on that.

You could have them tested. One of mine was bad and 2 were iffy. Replacing the whole assembly wasn't a lot more expensive than doing 3 individual ones plus the new ones are supposed to have a new design.

 

I dont think thats going to help I have a 1992 and have replaced tank gasket, fuel pump, Injectors, coil, plugs and rotor and cap... still dies at stop lights if I hit the brakes too hard or just regular stopping sometimes...

 

I can only imagine what the dealership soaked you to do that. When I changed out the SCFI assembly in my old '00 Bravada, the whole updated MFI spider was $350 from the dealership. If I had to replace more than 2 injectors, it was no longer cost effective to replace individual injectors. When you think about what the injectors go through and the crappy design of the original SCFI spider assembly, replacing the whole thing with the updated MFI setup just makes sense.

Why did you think it would help you? This thread is discussing a 2001 (and later 2002) truck... Vastly different from your '92. Please create a new thread on your problem in the appropriate forum section i.e. 1st Gen Tech (most appropriate IMO) or Engine & Transmission.

 

Having the same problem on my 2001 Blazer. Mechanic says timing is off 18 degrees and may account for at least part of the problem. Advised of the ICM angle mentioned by SWARTLKK, above. Will follow up if this bears fruit.