Recently I passed a car at high revs though I don't know if the engine "overevved" (an automatic - can it?). Immediately after, the engine ran rough. It was diagnosed as low compression on #2, head taken off, bent valve, machined, valve replaced, reassembled, ran OK. Belt did not appear to have jumped and tensioner was inspected and tested and said to be OK. 600 miles later after travelling on a highway at 65 mph, no high revs, pulled on to an off ramp, engine ran rough. Took it back to shop. Low compression on #1. Bent or sticking valve?

Anyone got any insight or suggestions as to a) what's happening and b) comments on whether the two events are connected or just plain bad luck?

One other clue or red herring. When head was reassembled and timing belt put back on - when timing marks on crankshaft and camshafts were aligned #1 cylinder was not at TDC. Is that correct?