Mystery bucking
 

Hey guys, I have a 2000 base model auto with 237,000+ miles on it. The tranny was rebuilt 3 years ago, as was the rear end. I did the intake manifold gaskets and valve cover gaskets, replaced the MAF, DPFEGR spark plugs and wires. It needs a lot of work still but my main concern is the car bucks/shakes/knocks between 35 & 45mph with light pressure on the accelerator. I thought it was the MAF because the car ran better with it unplugged.

Any clues as to what could be causing it? The coil pack is my next bet.

Some information to add. The bucking goes away if the car it's in neutral and reduces of I take overdrive off. I'm starting to think it's transmission.

Sounds like something in the engine. Sisters v6 was doing something similar not too long ago. We changed plugs, cleaned the MAF, throttle body and changed the coil. It ran great afterwords, no issue. The coil is probably your best bet, and it's not terribly expensive.

Torque converter shudder, that's the problem with mine, does the same thing