I am not the worlds best touble shooter but I have a bad vibration in my 1993 F-150 2x4 stght 6 cylndr. It only happens when there is tourque on the engine. Example. going down the road at 65mph. If I add more gas the vibration gets real bad. If I let off the gas the vibration goes away totaly.

Good tires. Balanced and all. There is no vibration unless I am adding power. The more power the more vibration.

No vibration at idle. No vibration when not in gear. worse in 5th than fourth. happens around the same tourque band in every gear.

180K miles. 5spd man. transmission.

any body got any ideas??

 

have you checked your drive shaft and u joints

 

Agreed. Check your u-joints, and look at your driveshaft for signs that a weight may have fallen off.

 

Thanks I will check the drive shaft and someone had mentioned balancin the drive shaft and check for missing weights. But where do they put the weights??Where should I look.

Again. Thanks for the input.

 

Look for what looks like two shiny spot welds, with nothing attached.