Chevrolet Repair: 1991 Chevy Berretta, coolant temp, crank sensor

Question
When the engine temp is around the 1st 1/4 mark or cooler on the temp gauge(where it stays on the highway), it runs fine. But, when it heats up when sitting in traffic or idling in the drive, the engine will kick and buck when you try to accelerate. The hotter it gets the lower the throttle position it starts to do it, to the point where it will not run at all. The radiator fan is running correctly and it never overheats, just seems to loose fire or fuel. Once you get up to speed and the temp comes back down, it runs ok again. I have changed the plugs, thermostat, aircleaner and run several bottles of injector cleaner through it. Any suggestions?

Answer
Hi Walt, This is not going to be easy to repair. I had a car that did this many years ago. Do you think I remember what fixed it,no. I'm thinking that the crank sensor was the problem but I'm not sure. You need to do I scan to make sure that all the sensors are reading the right readings as the engine warms up. The coolant temp sensoris one that comes to mind. The ignition module can also 2 cylinders to go down at times after it warms up.

       Sorry I can't help more        Mark