My 04 blazer ZR2 4wd starts up when cold with no problem at all but after about 20 to 30 mins or so when it fully warms up it starts spitting and sputtering then stalls. When I go to restart it right away it will have a hard time starting or not start at all. I've replaced the cap and rotor, new plugs, fuel pressure is good, new fuel filter, new crankshaft sensor because the check engine light came on and when I have it read it says crankshaft position sensor. I've put 4 crankshaft sensors in it so far. No difference at all. My catalytic converter was clogged so I cut it off. I believe the misfiring caused the cat to go bad. I even checked the throttle body to see if possibly it was dirty and needed to be cleaned but it was clean. At this point I'm lost. Does anyone with a similar issue with a 04 blazer zr2 have any suggestions? I can use the help.

 

ICM and or coil is getting weak

 

Thank you. I'll definitely check that next. I'll lyk what happens.

 

These engines also have the CTS (coolant temp sensor) that is run by the computer. When cold everything performs normal, when the engine gets to operating temp it can do exactly what you're referring to in many cases. The CTS sits by the rear spark plug on the drivers side of the block. Easy and cheap to replace.

 

Your good option here is to get the dongle and use any of the diagnostic software to pull out the data and analyze them (or post them here). Such a dongle will let You test CTS.
Is Your check engine still on? Does it appear when the engine starts? Or later on?
You may also want to check if You have 1" strong spark.