undercarriage scrape causing vibrations & check engine?
Riddle me this. The undercarriage of my 2001 Mercury Grand Marquis was scraped on a badly maintained driveway incline which apparently does this to every car there. I'm having trouble finding the impact point, but I believe it was pretty far up from the rear--the drivetrain maybe. I drove 30 miles okay after that (or possibly without noticing). Then the car sat for about a week, and now on its first drive I noticed a strange shaking vibration coming from the same area in the undercarriage. It's somewhat subtle, but when I got on the highway the check engine light came on, but immediately shut off when I decelerated. The vibration occurs on most acceleration and deceleration, and is worse to constant if driving above 40-50mph. If you try to glide (tap accelerator, coast, repeat) under 38mph it can be avoided.
Anyone have a suggestion? Maybe take the vehicle, drive it up the incline, and park it at high speed in the crap motel lobby the parking lot belongs to?