I have a 02 maxima with 145,xxx on it. When i am in 3rd or 4th gear and accelerate to 3 to 4k rpms and let go of the gas pedal the car bucks. In 5th and 6th gear it is smooth. What is causing this?

 

Motor Mounts.
Assuming the engine is in a decent state of tune, and no SES.

Look to the torque mounts first (nearest firewall and radiator), and then the pass./tranny mounts -- 4 total.
Do a search on motor mounts -- TONS of topics going-on right now about these.

good luck.

gr

 

BKM: If you hit 150K u need new mounts, new shocks, new fuel filter, new many things... the car just falls apart..

 

Sounds like normal maintenance on just about any car at 150,000 miles, not what I would call falling apart.

 

Well, hold on... what about 1st and 2nd gear? Are they more exaggerated or does it not happen at all?