Chevrolet Repair: stalling when hot, throttle position sensor, sensor values

Question
I have a 91 chevy pu 5.7 engine. It runs so, so at first, then when it's warm it won't hardly accelerate. If you give it very much throttle it will stall and die if you do not let off. Thanks

Answer
Hello Tom,
The ECM uses sensor values after it warms up, but does not use them when the engine is below operating temperature....it uses default values, which are not great for all ranges, but kinda average.
Sounds like one of your sensors may be giving a false reading.

One of the sensors I can think of right off that would make it run like that is the throttle position sensor.
I would test that. it can be done easily with a scan tool, but it can also be tested with an ohm meter. A constantly smooth transition all the way through the entire range of travel is desired...no skips or jumps.

Van