Iddle's fine, but durring acceleration it bogs down/hesitattion/studders. While in park when I bring RPMs up higher the motor will surge. I have tested the Manifold Absolute pressure sensor, replaced the TPS and cleaned up the Throttle body and Mass air flow sensor. I have also replaced the plugs and wires. Any help would be much appreciated. 2002 Buick Century 3.1L. Thanks
You definitely covered most of the bases. Considering all you've done so far, I would check into the fuel system next. First, how old is the fuel filter? Has it been changed? Yes, a bad filter can cause the problems your having. Next would be the fuel pressure regulator. You need a fuel pressure gauge to check it, which you should be able to rent from a good auto parts store. That will also tell you how good your fuel pump is, i.e. if the pump can deliver the necessary fuel pressure off idle. After that, I would check the injectors themselves for wear or blockage. A bottle of fuel injector cleaner in the gas tank would be a good idea, cheap, quick, and it wont make anything worse. If all that checks out, check your catalytic converter, a clogged or bad cat will also do what your describing. Good luck.
Theres one more thing, you should have coil packs for your ignition system. There should be 3 of them, with each pack firing 2 cylinders. Theres 2 small bolts that hold each one down, remove those bolts and take a look under the coil. If theres any dried up old grease or rust, take some steel wool or emery cloth and clean it up real good, same goes for the bottom of the coils themselves. Any corrosion will make a bad ground and will make the car sputter or misfire, especially when putting the engine under load. Clean it up and smear on some new dielectric grease and see if that helps.
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Thanks shocktroop40, I replaced the fuel filter 2 weeks ago. The fuel pressure at rail was 50psi with key on. There is no Chiltons manual for car so I still need to find out what fuel pressure should be. Ive also tried the fuel cleaners, no luck. I will look into the injectors next then the CAT if needed. Thanks for your thoughts, all ideas are welcome.
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