Replaced fuel pump and filter,plugs and plug wires and coil. Still shows firing problems on #7. I took out the no.3 and 7 fuel injectors and there were very nasty. I switched no. 3 and no. 7 iinjectors to see if the tester would changed the error to the no. 3 cylinder but in did not. Several times when I would change plugs and wires it seemed to have fixed the problem for a 1/4 mile or so. (problem is bad miss fire) for this reason I have a hard time thinking its a burned valve. Idle is very good it get rough when giving gas at say 20 plus mph. I desperately need help
