Cadillac Repair: engine stalling, fuel pressure gauge, throttle position sensor

Question
I have a 1994 Cadillac Concourse Deville. 32 valve northstar engine. The engine died the other day, I can start it and it will run. the second I hit the gas it dies. I changed the intake gaskets and it still does it. any suggestions? Thank you!  

Answer
Hi Gregory, For your problem it would be good to hook up a fuel pressure gauge and see what the reading is at idle and when you try to rev the engine or accellerate from a stop. There is a good chace that you could have a restricted fuel filter or weak fuel pump. Another thing to check would be the throttle position sensor/TPS for an open with your ohmeter as the throttle is opened. You would need to disconnect the wire connector from the tps and make 2 jumper wires that could attach to the tps terminals and to your ohmeter. Then slowly open and close the throttle from under hood while watching your meter and if the reading jumps around then replaceing it could fix the problem. Sometimes however a meter might be too slow to capture the glitch and useing a lab scope is the best way to look at the actual voltage that is created by the tps. With it there is no doubt if the sensor is acting up or not. After that scanning for codes might help. Otherwise there is a possability that one of the 2 crankshaft position sensors might be bad and can cause the engine to quit. Replaceing them both if one of them tests bad would be the thing to do. Visually if you unplug the wire connector and see oil by the terminals then it is bad. Also if you remove it and see cracking near the end with the magnet then it needs to be replaced. They are located on the radiator side of the engine behind the exhaust pipe.

    This can be a tricky problem to find because of the special test equipment required and you might have to take it to your mechanic if the above checks don't turn up anything. Let me know if I can be anymore help. Bill