94oldsdohc Posted June 5, 2004 Report Share Posted June 5, 2004 Last Saturday while taking a sharp turn, the engine started to miss and it went away afterwards. Later in the afternoon, everytime I accelerated from a dead stop, the car will start to buck like a wild horse. I will ease on the accelerator and then the engine speed will increase. However, everytime I have to climb a hill, the car will start to do the same thing again. I replaced the plugs, wires, fuel filter, PCV, air filter and also replace the intake gasket. The problem goes away after the sits overnight, then after a while, the problem symptom returns. Today, I replaced the fuel pump with a NAPA unit, did not replace the dampener, after driving the car for about 5 miles, the problem returned again! Do I have a defective pump? I will be doing a fuel pressure check tomorrow, nevertheless, it appears to be lots of pressure when I depressurize the fuel system. I had a Code 42 that came on when I jumped the fuel pump at the test harness and drove the car to bypass the relay. It cleared after disconnecting the battery. I am lost and would appreciate any suggestions what to look for. The car is a 1991, Pontiac GTP, 3.4 DOHC, Automatic. Thanks!! Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted June 5, 2004 Report Share Posted June 5, 2004 Sounds like you have a bad coil. When they get hot is when they brake down. buy one and replace one at a time. About 30. Jud Quote Link to comment Share on other sites More sharing options...
DaveFromColorado Posted June 5, 2004 Report Share Posted June 5, 2004 it also sounds like a pluged up fuel line or a bad pump or your pressure regulator isn't holding any pressure. get a fuel pressure gauage, and check the pressure at idle, and while driving (if you're able to see it when driving) those are the same symptoms that the focus's have when their two speed fuel pump starts to fail, they'll run in low mode all the time rather then switching between low and high. --Dave Quote Link to comment Share on other sites More sharing options...
94oldsdohc Posted June 30, 2004 Author Report Share Posted June 30, 2004 Replaced the ignition module and coils, the problem dissapeared for a while, nevertheless, it came back again. I do not have any codes, but the problem appears when the car reaches normal temperature. So, I replace the temperature sensor. Now the car starts and runs, but when I put the car in drive, the car dies. When I restart the car, sometimes it will miss and backfire, and it runs okay idling, but as soon as I put the car in gear, it dies. Did I disconnect something by accident? I know the temp sensor gives info to the TCC. I removed the crossover pipe to access the temp sensor. This problem is making me go crazy!!! Any ideas????? Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted June 30, 2004 Report Share Posted June 30, 2004 I had a problem that sounds exactly the same. It was a bad injector. Quote Link to comment Share on other sites More sharing options...
94oldsdohc Posted August 3, 2004 Author Report Share Posted August 3, 2004 Well...the saga with this car still continues... To this day, have replaced the following: Spark Plugs ICM Coils TPS Fuel Filter Fuel Pump Have injectors cleaned and flowed Replaced the intake gaskets Blocked EGR The car starts right up and drives well until I floor the car or is under load; it starts to miss, pop and backfire. I repalced the ECU with another one from a firend, and nothing changed. the next thing in the agenda is to replace the plug wires with the correct ones. I had replaced some of the wires with a set for a 1994 DOHC, however some of the wires were short and could not replace all of them. There are no computer codes. The EGR had been replaced with a new one, however it continued sending a code and now is blocked. Am I missing or overlooked anything??? I checked the timing belt and it is not frayed and it is not loose. Help is appreciated!! Quote Link to comment Share on other sites More sharing options...
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