1994 Mercury Grand Marquis Q&A

1994 Mercury Grand Marquis Question: 4.6L plugs are black, runs rough with no acceleration

I changed the fuel Pump and got no good results. -
Answer 1
Have exhaust system and cat. converter checked for possible poor flow\partially plugged condition. This will cause backpressure and poor running. Is your check engine light on? -
Answer 2
scan codes and post so we can adv. also ck fuel pressure,it may be to high due to bad fuel pressure regulator -