The kids were driving our 240 with 180,000 miles on the highway when the RPMs went up and then dropped to zeroand the car died. They had it towed to a shop and in the morning, it started but died within a block. The timing belt did not break.
The mechanic is confused. He thought it was the coil, but now is stumped.

Any ideas ab out what it is or how he should proceed to track it down?

Thanks. We love this car!