almost new motor with timing problems

[noslow1986]

cant seem to get my car to idle right i switch motor from an 86 to a 90. work fine the first time out . second time idle was way off tried to advance then retard still the same problem wouldnt idle. i didnt remove the distribtor when i swaped motor left it in .all i did was put the spark plug wires in and that look all good. could the whole distibtor be bad