1999 5.4 misfire

[99expe54]

so i recently replaced all the spark plugs in my expedition with motorcraft plugs(previous owner had ac delco in one cylinder bank and autolite in the other). unfortunately i broke the connector on the #3 COP but it was still in place just cracked. when i put everything back together i put the damaged coil on cylinder 5 to make it easier to replace when i got the new one. my truck started misfiring about 2 days later but it says the misfire is on cylinder 2 so i was wondering if the computer could be wrong or do i need to buy a set of coils(truck is at 180,000 miles). oh and the broken one had been replaced before as it was a different color and did not say motorcraft.

 

[chucks97expy]

If you only replaced the plugs then I would suspect the COP's need to be replaced. My 97's heater core went out and leaked coolant on the rear passenger side(caused the miss in mine) I replaced the heater core and then shortly after all 8 plugs and all 8 COP's. That was about a year ago. I bought my COP's from Ebay for about $100 for all 8.

 

[bedrck46]

with your mileage I would replace all the COP's or you could consider getting a new boot for the coil and just replace that for the time being Advanced auto or Autozone has the boots including wire When you pull the coil and boot give the boot a good inspection for any signs of a pinhole in the boot or any signs of dis-coloration in the rubber

 

[99expe54]

thanks guys I think I'm just gonna save up a bit and put new coils in it but I think my issue was caused by a leaking valve cove so I guess I need a gasket for that as well

 

[Kansas Gary]

Curious as to why you are thinking a leaking valve cover gasket is causing you miss on cyl. 2 ???

 

[99expe54]

I found what seemed to be oil and dirt down in there and I know that valve cover leaks a little just never been brave enough to try and get it out of there to replace the gasket because of all the things in the way