I own a 2003 Scab , 5.4, 4x4, and have not had a lick of trouble with it. I talked my father into buying a 2005 Screw 5.4, 4x4. The truck had a bad misfire with 3,800 miles on it. The dealer replaced /repaired the coil on plug system and said that would be the end of the problem. My father went on a road trip and the misfire started again in the middle of the desert on the way to Las Vegas. He had to drive it about 70 miles with the misfire. A dealer in Vegas repaired the COP's again. I just wonder if any other issues will surface due to the fact that the truck was driven with the misfire. Any possible damage to sensors or catalytic convertors or anything for that matter. He is taking it to a local dealer today for an inspection, anything i can tell him to watch out for or ask about would be appreciated. Thanks.

 

Anyone?

 

Return to dealer. Warranty item. No charge...

 

It's not likely that any real damage was done. Cars have driven for thousands of miles with two or three plugs not firing with no problem. On a Cat equipped truck you would be putting unneeded wear on the converter, but maybe in three or four thousand miles he might have caused some damage. Or not.

Do you know if the same coil went out both times? If so, I would forget about it. If it's two different ones, I would ask about bad production runs, etc.
Still not a big deal while it's under warranty

Misfiring is not the same thing as cross firing or pinging/detonation, which can seriously damage a motor. Misfiring just means some gas will go through without burning.
And you loose power, maybe idle rough.
Chris

 

If the check engine light was on and you had a dead misfire.......the computer actually turns that injector OFF to that cylinder. This prevents the raw fuel from being pumped through the dead cylinder and into the catalyst which will severely overheat and burn it up if driven for a long time. So as long as you had a CEL and a code was set for misfire, then don't worry about it because it should have killed that injector.