To the Doctor:
I have a 2006 Pontiac Vibe with 147,000 miles on it. It has been maintained very well with all scheduled fluids changed at its appropriate time. The question I have is that even after all motor mounts, shocks and brakes have been newly installed, a complete front end job has been performed and, finally, a complete tune up, the car continues to shudder or shake. When making a tight U-turn, it will also hum eerily, as if the car were possessed. Any advice would be appreciated.

The Doc Says:
Did some checking around, and it appears that vibration is a common problem among Vibe vehicles. I can say from experience, though, that occasionally tires are a major source of vibration. Don't know how old yours are, but you might want to have them checked by a reputable tire shop.

As for the humming when turning, I haven't come across anything specific to the Vibe, but I do know that some other GM and several Honda vehicles have had issues with the differential "humming" whenever the car is put into a tight turn. Generally the cause of this "humming" is contaminated differential fluid. If it's been a while since you've had the diff fluid changed, you might consider having that done. Unfortunately, if that doesn't fix the problem it could mean there is an internal problem with the differential, though before doing anything drastic I would have a mechanic definitively identify the source of the noise.

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