This is a great forum, i've found lots of great information for my newly acquired GTP with 168,000 miles. Thanks ahead of time for your help.
The concern that i have is driving me crazy...when i first got the car, it had horrible grinding noise from the front end, especially when turning right. I thought by just replacing the left front bearing, it would solve my problem. I replaced left and right hand front wheel bearings because it needed them. Noise was almost gone, but still not quite.
While replacing them, i noticed the front brakes were very low(almost metal to metal on RF inner pad). Replacement of front and rear brake pads with discs were done a week later.
Soon after, when accelerating lightly, it would feel as if I had a misfire. I proceeded to replace spark plugs, sure enough...spark plug wires separated on #5 spark plug. I held off replacing right hand bank plugs until wires arrived a week later. I just replaced spark plug wires and plugs on 2,4 and 6 cylinder last week.
This is where it gets good...finally, thinking I was gonna have a smooth ride, I take it out for a spin and notice when making a right hand turn, at slow speeds~5mph, a rotational type sound coming from left hand side(kind of like a scraping type sound).
I thought i had left something loose. i didn't drive the car for a couple of days, finally yesterday removed front wheels to re-inspect my work. Everything is torqued to proper specs.
Once again, I hit the road.
Some of my observations...
When driving in residential zone, traveling 25-30 mph, if i go over an imperfection in road like a dip where only left hand suspension drops(right hand is stable), it sounds like a clunk which I can also feel in the floorboard. Once i hit 40-50 mph, it almost feels as if i still have a misfire, yet i believe it's my drivetrain that is "bouncing around", reason i say this is because it is most noticeable when the road is curving to the right and once again i'm able to feel it on floorboard. If I happen to let go of accelerator while experiencing "misfire", I hear a faint hum from under center.
Lurking around this site I see that differential problems are not out of the ordinary, especially with this high mileage. My trans fluid is very dirty, fluid change was next on the agenda. I think I've got something going on with my differential where my left hand axle is bouncing around a little more than it was designed to.
I hope to get some feedback on what i've described.