03 gmc sierra 1500 5.3 liter stalls after reaching normal operating temp and wont start until cold again

[forrest deen]

Hello!I am Forrest from the ForrestMelissa post above.My truck is a 2003 gmc sierra 1500 4x4 5.3 liter. I have replaced the fuel pump, fuel filter , mass air flow sensor, air filter, throttle position sensor, map sensor, fuel pressure regulator, spark plugs, wires, all 8 coil packs, evap canister purge valve, crankshaft position sensor, and the pcm. The truck starts up first try when it is completely cold and it will idle fine until it reaches normal operating temp and the it sputters and stalls out and won't start up again until it is completely cold again. I am at a complete loss on this. I am no mechanic by any means, but I have had to learn as i go because I cant afford to put in a shop and I don't necessarily trust most shops anyway. If anybody has any ideas I would greatly appreciate some help. My truck has been down for 2 months now. I have had to borrow a vehicle for work. Any help would make a difference. Thanks! Oh, Ialso replaced all 4 O2 sensors and the fuel pump relay.

Edited October 30, 2023 by forrest deen
added parts i have replaced

[bubbanbrenda]

any codes?

[redvett]

Your going to need a bi directional s canner to properly interrogate the PCM and see what is going on, all the parts you have changed are mostly wasted money.

I would think the CTS might be going bad and cannot tell if the engine is hot or cold, it tells the PCM how much fuel is needed to start a hot engine much less than a cold engine.

Quit spinning your wheels and wasting money and have a shop look at the vehicle since your not able to diagnose it.