This is a head scratcher to me. 03 Tahoe 4wd, 110k miles , new tires. I got a vibration between 65 and 75mph. I set the cruise in that range and I got a good vibration throughout the whole car, I can't isolate. I up it over 75 or under 65 it goes away. If I'm on the gas in the 65 to 75 range it vibrates, when I let off let off and coast it goes away. The second I touch the pedal it starts wehn I coast it stops. When I start from 0 it starts to vibtrate in and around 2nd gear but not as severe. U-joints are tight and front end is tight. It almost acts like when I hit the gas the engine starts missing but the engine seems to sound good. Before I start getting dirty and spending money anybody have any Ideas? Thanks

 

U joint might be frozen. The proper way to check a u-joint is to remove the drive shaft and feel them. They should move freely

 

Thanks, they're pretty rusty too so you might be right on. I'll let you know if that fixes it

 

Yes rear driveshaft u-joint had 1 set of needle bearings gone and rusted out. little boot was on but had to pull drive shaft to discover. Fixed the vibration! Good note to others. you need to torch each cap to eject that plastic filler they use to lock the caps, then a hammer, a 1-1/8th inch socket and a bench vise was all I needed, thanks