I have a 2003 SS i got used with 20k miles in november of 2006. Since then i mostly used the car going back and fourth to see my girlfriend in college (Cleveland, Ohio to Tampa, Florida) so the miles are all highway, currently has 83k. I noticed at around 65k when taking a right turn the car would shake, but only when giving it gas, if i coast into a turn it rides fine. Also when accelating hard on the highway it will shake, but if i let off the gas it goes away. Also every now and then while making a hard right turn the ABS light and Trac Off light come on, and the info center will say "Service Traction System" but they go off after restarting the car. I first noticed the problem in jacksonville fl on my drive home, after getting home i took it to my mechanic, who took it to transmission specialist and pretty much told me he had no idea. 6 months later i took it to another mechanic who in turn told me "i have no idea". I have searched every auto forum on the internet and have not come up with an answer. If i can't get this figured out i'm gonna have to eat the negative equity and trade the ol' girl in. Now i have spared no expense in taking care of this car, oil has not gone more than 3,100 miles without being changed (Mobile 1 full synthetic), trans fluid has been changed every 20,000 miles, fuel filter every 5,000 miles, coolant flushed every 10,000 miles, and fuel system cleaner every oil change. The only work i've had to put into it so far is rear tie rods, stabilizer bar links, and front pads and rotors all at 55,000 miles. I think i've covered just about everything. Has anyone else had any of these problems?? and if so, how do i fix it?? Thanks in advance.

Two more things. Sometimes when turning the wheel i hear a popping/pinging noise, and the rear defogger hasn't worked since.....well, i don't remember it ever working. Were thse common problems on the 03??

 

Check the clips in the rear window for the defogger problem. Sometimes they break.

As for the main question I'm not the best at transmission and steering, but I would think it has something to do with the differential.

Anyone else feel free to chime in on this one.

 

have a mechanic check ur right cv joint, even something minor like the angle of the joint can cause vibrations

 

abs and service traction control?

check the bearings? may need a wheel assembly hub?

 

Go someplace where you can get the car on a lift that will allow the front end suspension to float.
Check everything on that Hub for tightness and security.
Look for anything that might cause the ABS Wheel Speed Sensor to lose its accurate positioning over the the ABS Wheel Speed Sending Ring on the Hub.
If the Hub is loose, or the CV Joint beginning to fail, the Hub Speed Sending Ring's SIGNAL to the Sensor could drift enough to interrupt the constant signal the ABS System detects the intermittent signal and deactivates the ABS capability.
The Light coming on shows you when the System is down due to the tracking error of the Wheel Speed Sensor.
Something is loose ... or, there might be damage to the Speed Sending Ring on the Hub.
If the Hub's Speed Sending Ring is damaged ... you need a new Hub.