I haven't been able to figure this out so any help would be great. When I get to 40 mph and the transmission shifts into overdrive (4th gear) I get a vibration in the gas pedal. If I accelerate right through 40 to past 50 mph it doesn't do it. It gets really bad if I have to keep my speed anywhere in the 40's. It feels like when you drive over the warning strips on the side of the interstate only not quite as severe. I only feel it in the gas pedal, not the steering wheel.
V8, 180K, Automatic. Other than that it runs fine. I won't mention what I've checked so far so as not to influence your thoughts. Unless you guys think I should.
Thanks in advance, SIO3