Sounds like you fiddled with the wires first, and then it drove fine? If so, IMO that's a smoking gun pointing to some type of electrical issue, such as a cut/broken wire. Could of course also be a bad connector to some part such as the coils, or maybe even a part (coil, etc.) that "reconnects" internally for a short time after stuff was moved around. Maybe a multi-meter test on various points in the system might reveal the problem.
Did you suggest that the stealership "relearn" the tech who told you the timing belt had slipped?![]()