My 94 vert experiences vibration when accelerating at speed between 28 - 35 mph.Vibration immediatley quits if you let off the gas. I had the local shop look at the front end but they didn't find any alignment / suspension issues. Any ideas?

 

Do you feel any misfire? Could be anything really including engine mounts.
How many miles on it btw?

 

also might be u joints in the drive shaft? my s10 had this problem years back

 

Get the tires checked, it sounds like one might be defective. I had the same thing happen on an old pu I bought. The thing was so bad between 30 -40 mph it was impossible to drive all because of one tire. It looked perfect on the outside. On the spin balancer it almost tore their balancer apart..lol

 

Well I don't think it's the tires, I had them checked a couple of months ago when this first started. I hadn't thought about the U joints. It has 116K miles on it and I have recently replaced plugs/wires/ and fuel filter.