Engine problem
1994 Lincoln Mark VIII V8 Two Wheel Drive Automatic 169335 miles
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My Lincoln Mark VIII has a 4.6L engine that has to this point been very reliable but recently on a trip to Georgia when i push on the accelerator and the car gets to 50 mph the car starts to vibrate and it drags. this continues until i reach 60 and then it runs smooth again until i get to 70 and the vibrating comes back and i get a slight drag in power. Now i hooked my car up to my car engine computer and i took it to an auto shop and they hooked up to their computer, and got the same result,no fault detected. Please help me as i have a 1995 Mercury Cougar and a 1993 F-150 with similar problems.

Have you had a tune-up done on the vehicle recently? Does it feel like an engine miss?

Yes the Lincoln was serviced twice, and the F-150 and Mercury was serviced once....still no difference. So I really don't think it's an engine Problem. I do think it might be a fuel pump problem, because i've never replaced the pumps on either vehicle.

i would be leaning more towards a spark plug or a plug wire.. if it were a fuel issue you would notice it if you accelerate fast from a dead stop and while you were at high rpm the vehicle would bog and not recover..

I Changed the spark plug wires already and the Mercury cougar keeps running the same way, and the Lincoln has fairly new wires on it. Is there a special way to put the wires in? If so please tell me as my vehicles are dying and I need them to get around town. And if this isn't the Problem, please tell me what the hell else can it be? Thank you