My blazer stalls when driving in the heat (97 degrees and above), usually when I'm accelerating, and sometimes when Im on the freeway. Took it to O'reillys to have the check engine light, threw out a P0351 code. The guy who did the test said its a primary coil misfire and I should replace the coil. Does this sound right?

 

Interesting, never had one give that DTC before. The DTC means there is a problem with the signal from the ignition module to the ignition coil. Could be either one, or the wire between them. Could be a tough one to duplicate for troubleshooting too. If it loses ignition only when it's hot, it's more likely the module than the coil. The ignition module is far more sensitive to heat than the ignition coil. You can try removing the module, clean the back side of it, and the heat sink, and cover it with this stuff: Heat Sink Grease (6g) : Heat Sinks | RadioShack.com It helps transfer the heat from the module to the heat sink.

 

I had the module tested at auto zone, and it tested fine (they said). I'll try that heat sink grease, tho. Thanks for the feedback. Stupid auto correct. Hard to be thorough at 4 in the morning.

 

Better fix your auto correct and try again

 

Trouble with the AutoZone test is that the module is not hot..... unless you brought a hair dryer to get the IM hot during the test.

Try what captain suggested.

 

So I bought a new Delphi ICM from RockAuto, and now the CEL is off, but still stalls in the heat. Is this a vapor lock issue? Had everything in the charging and the ignition system checked, replaced ICM and Ignition coil, and still having issues with stalling in hot conditions (outside temps over 95 degrees), getting frustrated.

 

Vapor lock is not a problem with a "pusher" fuel pump...at least my understanding. However suggest checking fuel pressure when engine stalls as the fuel pump may be failing when hot.

 

I have a similar issue it seems my 4.3 engine in my Jimmy stalls when its hot upper 80s to 90s. It seems to do it only when I am at a stoplight or at a stop sign. I think it tends to stall more often when the fuel level is low in the tank. Do you think that is a sign of a fuel pump going bad? I guess its not a vapor lock from what you just said about the system.