1998 Pontiac Grand Am



November, 21, 2012 AT 12:11 AM

My car is shaking and jumping and I can not figure out what is wrong with it. It is throwing out a P0300, which is a multiple misfire. I have changed the following parts. Sensors: camshaft, crankshaft, coolant temperature, throttle position, and the fuel preasure regulator. I have also changed the timing chain, the spark plugs, fuel filter and both of the coilpacks, and it has not helped one bit. When it idles, it will not rev above 4 rpms. It will stall some times when I put it into drive. When it doesn't stall it shifts fine, but it will still not rev above 4 rpms. I am all out of Ideas. I am going to change the PCM, but I want to make sure I cove every possible avenue, before I do it. If anyone has any suggestions they would be much appreciated. Also the EFS off light will come on with the check engine light, and the only way you can get it to turn off is to reset the error code. It will stay off for a few minutes, then come back on with the check engine light.

1 Answer



November, 21, 2012 AT 12:17 AM

Check fuelpressure as low pressure will give this and check for a vacuum leak. You probably spent all your money on sensors needlessly. Also clean your throttle plate on both sides with choke cleaner. It should 41-47 psi with key on engine not runing

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