farmalldxe

Hey, first post. My 2011 F150 5.0 has 167,000 miles on it. Meticulously maintained, excellent condition. Only thing ever replaced has been spark plugs. Starting about 2,000 miles ago, I would experience the whole truck shaking at speeds of anywhere from 20-50 mph. It doesn't last long, maybe 10-20 seconds. I've pulled over, stopped, and it disappears every time. Engine doesn't miss a beat when this is happening. I should mention that the tranny was flushed at 40k and again at 160k at the recommendation of the service manager at the Ford dealer that has handled my truck since new. They had it up on the lift and couldn't find anything. Any ideas? Thanks