Toyota Celica Loss of Power

I have a 1987 Toyota Celica. It’s always been a reliable, peppy car. Recently, though, there was a mishap. While driving, a few weeks ago, the engine just quit. Got it to my mechanic who found that the distributor shaft had come out of it’s hole, wherever its supposed to fit. He put back in, but since then there’s been a noticeable loss of power. It just doesn’t accelerate like it used to. My mechanic has checked and retimed it - more than once. We’re both stumped. I can’t help but think that something else happened back when the engine quit. Any ideas, aside from getting rid of it altogether, would be appreciated.

 How about the spark plug wires?  How old are they?  Could the distributor be worn so it can no longer keep accurate timing? Has it been checked on a scope to assure it keeps consistent timing?