I just cleaned the battery posts and and reinstalled. All grounds are tight and clean. The plugs were replaced recently and the vehicle ran much better but after a few weeks it went back to the way it was before. A few of the old plugs were black and oily. All leads are clean and in correct order. I would appreciate if you would give me a step by step on how to test the alternator and fuel pump? I had an auto parts store test the alternator and they said it was ok. I'm pretty sure the O2 sensors need replaced since I can hear rattling in the catalytic convertors. Thanks for your help.