why is my rear end of truck is swaying? on 2002 Infiniti QX4

i own a 2002 qx4 with 116k miles I had new tires and wheel alignment done. 2-3 months later the rear end begins to sway while driving when I press and release the gas pedal. Havent driven it to much since then but now it just feels terrible. Does anybody know what might be wrong?

2 answers 1 comment
if this occurs after about 40 mph and feels dangerous like your going to flip over you have to replace the rear trailing arms both R/L upper and lower
My 2002 is great but has two problems. 1. go over the smallest bump and the rear end sounds like an axle dropping from a foot in the air with any speed. 2. while stearing, and making a curve,the stearing wheel jumps 3 or 4 inches one way or the other as if if were 67 camaro that needed a idle arm with no busings to tighten up the stearing. Any suggestions. Please reply. Thank you, Johnny
If the original repair shop is your trusted facility I strongly suggest taking it back for an inspection, if not take it to a well known alignment shop for an opinion and estimate. Sounds like a suspension part in the rear is loose or worn out.