Hi all, my name is Mike im new to the club. Did multiple searches and no luck. It seems at higher speeds (above 80 mphor so) the back of the car sways left to right as if i had a low tire.This is my first post, so not sure if i did it in the right place.

 

It would help if you told us which car this is.
also list your mods.
When was the last time you had an alignment by a competent shop?

 

Have you jacked the car up and shook the rear tires to see if there is any play?

 

check suspension toe links and arms...mine did this a long time ago in my R1. Around town it was fine but at speed the rear seemed to float. Turned out my toe links had loosened

 

88 TII. 13b cosmo p-port, 1200 pri 1600 sec inj, projay intake and tb, aeromotive a1000 fuel pump with regulator, s400 turbo, tial 60mm wastegaste, tial 50mm bov, front mount ic, exedy twin disk and flywheel, stock tranny, custom header and 3 1/2 exhaust (no cats) microtech lt8s, energy susp master kit front rear tokiko susp, msd coils, custom engine mounts and reinforced rear end by junior, built and tuned by junior. 591 rwhp 25 psi on Q16 due to ecu's 3 bar map sensor cutting boost at 28 psi. alignment was done 4-2010, (belle tire) rear wheels feel solid. any help would be greatly appericated. thanx

 

The injectors, bov and fmic and other engine mods won't affect your alignment.

When did this start? What is your current suspension setup?

Your post looks like you threw up and a bunch of parts came out. I don't have time to decipher what your suspension setup is. Make it easy on us please.