The car started vibrating on a trip to Orlando Fl from Kansas City. Had new set of Goodyear tires. All wheel weights had fallen off. Had rebalanced at Goodyear Dealer in Orlando. Still vibrated and front rotors checked at a Midas Dealer of course they said rotors were warped and I need back drums. This cost 500 dollars, a real ream job. Still vibrated. Drove back to Kansas City at top speed of 60 mph.

Back to Goodyear dealer, had tires replaced and replaced 3 times and one new rim for nothing. Still vibrated. Rims cost $150. Took to transmission shop to check for vibration there, checked out ok, no charge. Took to Pontiac dealer, they rebalanced and said Goodyear tires did no keep balanced, still vibrates, lost another $100 to this dealer. Went back to Goodyear, they replaced front struts and rear shocks, still vibrated, cost $400. Car still tracks straight.

Its a seat in the pants vibration. Goodyear replaced whole rear end axle assembly. Still vibrates. No charge, they put old axle back on. Replaced rear brake drums, still vibrates. Goodyear replaced CV joints and axles in front. Still vibrates, put old CV joints back on. Goodyear vibration equipment on car, found nothing. Still vibrates. Goodyear sent car to another shop to to get tires spun balance on car, tires balance okay no vibration while spinning. Back to Goodyear and car still vibrates.

Since this problem started I have put on 30,000 more miles and the vibration is still there. Seems to be affected by certain road patterns. This is an all plastic and fiberglass car, could some bonded joint in the frame and body have separated somewhere or could the the exhaust be vibrating at certain speeds? And why did GM stop making these vans out of plastic and fiberglass? Was there a engineering problem with this car?