Also you should check to see if you have any codes on the computer. Even if you dont have a check engine light you can still have codes present.

 

It does it when I'm cruisin not givin it much gas.

 

if it does it when you're coasting I wouldn't think its fuel related. I would think low fuel pressure would be noticed more under acceleration. But you could still hook a gauge up and check to make sure. Have you checked the rear end and transmission fluid levels?

 

Put a new fuel filter on first, thats the cheapest thing to try. I'll bet its either that or your pump, I had a 91 that did the same thing, would shake like hell when I gave it gas and it didnt wanna go anywhere. Ended up being the front tank pump. If ya cant borrow a fuel press guage from anyone just see if you can get a cheapie from a parts store and check it.