I changed the fuel Pump and got no good results.
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1994 Mercury Grand Marquis Question: 4.6L plugs are black, runs rough with no acceleration
Answer #1csubak30 September 12, 2013, 00:08Master
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 #2Greg's Orange Auto (15229 Answers) , Orange, CA - (714) 361-9386globalhelper September 12, 2013, 09:07Master
scan codes and post so we can adv. also ck fuel pressure,it may be to high due to bad fuel pressure regulator