Ok guys

2000 3.4L V6 with 80k miles: The transmi$$ion was rebuilt at about 73k (literally 5 months after buying the damn thing) and now I have a new problem... It started like 2 weeks ago, I noticed the car shaking (Id say mostly in the pedal but seemed like the whole car) while accelerating. At first it only happened a couple of times when on the ramp to get on the highway, and now it seems to happen quite frequently, even around town going like 30-40 and especially when going uphill! It seems to be shifting ok though... I know nothing about cars (haha) but was hoping someone would know whether this is a sign that my transmission might still be f*d up... I also read that it might need a front end alignment, or maybe something to do with the weights in the wheels, could it be spark plugs? (like I said I know nothing, these are just basically suggestions from people Ive talked to - nonmechanics...)... anyways I know its not enough info to diagnose the problem and Im planning on taking it to a mechanic when I get the chance.. but is this common and how much more money do you think Ill have to dump into this pos??

Just a suggestion here...might be able to pin-point by rotating tires front to back...this will help eliminate lost wheel wts, broken belt in tire if handling characteristics change. could be one or both tires...probably one most likely. Could also be broken or loose motor mount (or cradle bolts) so inspect those as well, in any case work from the least costly scenario to higher cost such as CV joint. with info you gave this is the best I can do for you

Oh forgot to mention to check your lugnuts. could be loosening, 100 ft lbs is spec, but equally tight is most important to prevent brake rotor warp which could also fit into your question but you would feel that in the brake pedal during braking

I was talking to a tech friend yesterday and he said if the shaking is in the gas pedal you want to check the vacuum hoses carefully for wear where they might rub against something or loose connections. Even the smallest of leaks can cause problems. I know I found one behind the air box somewhat worn on the underside of hose so I taped it with electrical tape to prevent wear thru.