89-- chevy s-10 4 cyl -5 speed problem

Question

when its cold, it runs great, when it heats up it cuts out and sputters ,i just changed the throttle body from a spare moter, and no luck, same problem,,when i look at the injector while its running after it heats up ,its not a steady spray, and it backfires when i give it gas,,its just fine until it heats up,, is this a sensor problem,, or what,,i am desperate for help on this ,,

Answer 1

Temp sensor on the thermostat housing.  It is reading -41 degrees so it is ok when engine is cold but intolerable when it warms up.  A quick check can be done by disconnecting this sensor and the computer will assume a 180 temp and should run ok but might be a little hard to start when cold.