Shaky, bouncy, loose suspension
 

2007 GMC Sierra Classic body style 4.8L V8 4L60E tranny 80k miles. Looking for advice where to start to correct my suspension problems since I have several. I bought the truck in December 09' and the previous owner installed new shocks about a month prior, the truck has been bouncy/bumpy since I bought it but lately it has gotten much worse. I was about to buy new shocks even though these have relatively low miles on them, but I just installed new 22" wheels and after putting these wheels on and looking at the taller tires the gap seemed smaller between the top of the tire and the bottom of the fender. I pulled the tape and the driver side is sitting 3/4" lower than the passenger side. Could my coil spring be bad on a truck with this many miles or should I be looking somewhere else? I just had my alignment done and wheels balanced and the truck is still riding/handling horribly what's the most common parts I should check and what should I actually look for in checking the individual components?

Also my guess is sway bar bushings in the rear when in a corner if I hit a bump it almost feels like the back end of the truck lifts up and steps out to the opposite side of the curve.

I'll apprecciate any help you guys can give me, I've never done any mechanic work on any of my vehicles until now but after doing a little work on my truck all I seem to want to do is work on the truck either repairing or upgrading it, I'm pretty mechanically inclined I just need the know how and experience to point me in the right direction. Thanks

Also completely forgot to mention my brake issue which is most likely a suspension problem but someone may have some helpful input. At certain speeds and especially on certain roads or sections of road my brakes are pulsating. I put brand new rotors on expecting to fix the problem with no difference. I'm thinking it may be worn hubs in the front but I'm not 100% sure they are worn and I'm not sure how to check the bearings, at $200 a piece these are not something I want to swap and see.

Coil spring on 1 side could be weak. Has the truck ever had and damage to it from a wreck or running over something in the road or off road really hard? Such as a pothole, boulder, tree, etc? How much air pressure are you running in your tires? I know with my tires if I run anything over 38 pounds of air pressure I get the bouncy, loose feeling in the rear.

I run 35 PSI in all 4 tires. The truck has never been in a serious accident where body repair or anything like that was needed. The previous owner happened to be a personal friend of mine and he's nuts. I know that he very well could have tried to jump a hill or something crazy. To check the coil I pull it out and measure? Where would I be able to find a spec for overall length?