sounds like like your radius rod bushings are worn out .( just underneath bottom of radiator sits ) .need replacing or if stiil good tighting that big 1 1/8 nut ,,, my dads little 1989 mitsubishi COLT used to do that also ,,,i took it out and thrashed the helll out of it and when you hit a bump or brakes it would pull left severly changed the perished radius rubbers ,,beutiffullllllllllllllllllllllllllllllllllllll

 

check your ball joints too
i just did the bottom ones...that dont take as much load as the top
the play was enough to make the car feel unstable and wander about abit on the bumps
also toe-in settings can make it feel like it is "tram tracking" with any deviations in the road surface.
this might sound nuts, but one member here found most of his problems solved when he put an engine cross member in the car...it didnt have one!!!!
good luck.