i have a 92 chevy truck with a 350..it starts and runs perfect when cold but when it starts to warm up and you give it gas it starts missing and backfires up through the motor..has new plugs, plug wires, and fuel filter

 

Try changing coolant temp sensor... located beside of thermostat housing.
This little sensor has all sorts of symptoms.. cost about 10 bucks.
Get it out of the equation. See if it helps.

 

changed coolant sensor didn't make any change...also forgot to add that after you drive it around and get it warm then shut it off its very hard to start...anyone know what else it could be...

 

Check fuel pressure 9 to 14 psi. Could be map sensor. Check coil maybe getting hot.
But sure has symptoms of cts.

 

Did anyone figure out this problem, I know it not the throttle positioning sensor. Please need help?

 

Did you ever figure out the problem? Please let me know if you did.

 

the tips on the inside of the dis. cap was dirty..