I have a 97 4runner SR5 2wd. My favorite vehicle ever! I bought it with 80,000miles and now have 230,000 miles. Ive only done tune ups and oil changes up until last month when i put in a new radiator, time belt, water pump , pulleys, and all that. Drives great until Friday. I got off the free way on the way to work and it felt like i was driving over lines on the road when i got to about 20 MPH. After driving it home later that day i found that it vibrates like that any time i give it gas. no matter what speed over about 10 MPH. If I'm doing 70 it vibrates and feels like its kinda grogging down. If i let go of the gas peddle the vibration goes away and its smooth. As soon as i give it gas and i feel it accelerate everything vibrates. RPM is about 2000 so it good. And it shifts fine. And in park or nutral it runs great and smooth with gas. My tires are due to be rotated so my thought is to do that and balance first but riding smooth at 70mph while no gas tells me its not that. Stearing wheel vibrates but dosnt shacke, and i dont get a shake when i use the brakes. I feel the vibrate in the gas peddle, on the automatic gear shift and the mirror gets fuzzy from vibrateing. Maybe drive line balance or u joints?

A little extra info was the day before i heard a snap underneath or something not to heavy hitting underneath the truck. I drive an hour and a half to work on the freeway so once in a while i get some type if garbage underneath or a lug nut from another car. When i hear the noise i looked in my mirror and didn't see anything in the road. I then drove an hour to work, And hour and half back home and a hour and a half back to work before noticing this problem. Maybe just a coincidence? I have to drive back to work on Tuesday and I'm low on cash till Wed. But I'm very worried about driving it. Right now I'm going to pull the drive line and look at it for Blank spots ( weight broke off maybe) and loose u joints though i don't really know what to look for if there bad... Any help?