I have a 2003 f150 it idles and drives rough but my check engine hasn't came on

Can guess at it from now on!... Have it scanned to see why it running rough... Not at a parts store, they can't do a real scan test! Scanner can run cylinder contribution test for COP (coil on plug) ignition along with many other test...fuel trims for possible vacuum leak, sensor data etc.

Sounds like a bad spark plug or wires.

OWNER!your truck don't have wires!has a coil for each cylinder,8 of them.take pushrods advice and have it scanned.you could replace a grand or more worth of parts before you find out it's only a $100.00 part or less.believe me,i have the same truck you have with the same engine,except mine is a 2000 with 306,000 miles on it!still a going!!