[davemc53]

Every once in a while, when at 40-50 mph, it feels as if the engine or transmission badly "misses" or something. It jerks badly enough that it feels as if it is hitting a bump. But it only does it once, and then not again for as much as several days. A couple things I thought it might be:
Transmission slippage?
Water is gas?
Car has 140,000 miles on it.
Any ideas or similar situations and what you did to fix?

Thanks