Thanks to everyone responding to the posts, including some responses to another post. I made the 200 mile trip without issue, until I got home.

I believe what happened originally was that the weather which went from rock-solid frozen to complete thaw (lots of snow and mud) and then to rock-solid frozen again created some imbalance in my wheels, particularly the front. I must have had a chunk of something heavy. This created imbalance / vibration which went off the chart at speeds in excess of 60. After washing out and inspecting, I made the trip down. About halfway, I stopped to replace the rear tires (I needed to do this anyway and thought the one rear passenger tire was the cause). Well, after this, I got back on the road. I still noticed unusual but subtle vibration. I ranged from 60 to 80 and the vibration (which could be felt in the steering wheel) was about the same the whole way. Nothing alarming or unmanageable, just...different than before.

Then, I was driving close to the house and hit some bad road a significant bump or pothole. This caused the front end to completely lose it; i felt as if the whole car was going to disintegrate. I was driving at a speed of between 55 and 60 (thankfully). I was able to control the car during this chaos. I put my blinker on, and slowly slowed down and slowly eased off the road. Literally, all items on my front passenger seat flew off. The airbags did not deploy, thankfully, but I can't see why not given the violence of this shaking. Now, here is the weird thing. As I slowed down the car totally stabilized, rolled forward smoothly, and, as I accelerated from not quite stopped position, went on its way without incident. I checked everything out when I got home. My washer fluid reservoir cracked, and leaked, but nothing else. This a.m. I started the car, same as usual, drove away with no issues and made the daily commute. I drove slower than usual (between 60 and 70) and avoided all the bumps (I know every one of them in the 46 mile journey). On smooth pavement there is little to no vibration (in other words sometimes the vibration is there sometimes it is not), but I know this problem can and will happen again.

What on earth was this? I am afraid to drive the car now. I don't want to cause an accident or injure myself or someone else. How could the car run solid and feel fine at once and then do this in a moment's notice, and then go back to normal? I don't know if this can or should be fixed at this point, or if I should start getting the 400E up and running (money wise, I do not want to put money in both cars and the 400E has 100K less miles on it but needs radiator, fan, fan clutch, belt, brakes, and some rotors. $3500 all told).

Thanks, CJTucker

1992 300E (4Matic) 252,000 miles
1992 400E 150,000 miles

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CJTucker