99 Expedition #4 Misfire

[latigo1]

Hi, Just bought a 99 Expedition with 160,000 miles and have a question.
Got the code for a #4 cylinder misfire. Had a Buddy of mine with much smaller hands change out my plugs for me. Told me the plug for #4 was covered with an oily almost tarry substance. Wiped it out as best he could and installed the new plugs. Truck ran great for about 100 miles. Now I'm getting the code again. Ran fine one day started it up 3 days later and running rough again. Is there a leaking gasket? Any other ideas? Reset the computer and light isn't on again yet but running real rough.

Thanks for any help

 

[thereason21]

I got the same thing goin on right now ... the coil pack on that cylinder is bad it appears ....

 

[supermario]

I got the same thing goin on right now ... the coil pack on that cylinder is bad it appears ....

+1, My brother kept having the same problem, it was coil packs going out one after another. We bought the 8pack of coil from Summit Racing and changed all of them at once. No problems since then. Mechanic did say that there can a water leak someplace that is making the coil packs go out.

 

[latigo1]

Thanks for the help. What about the sticky substance on the plug? Is this caused by the misfire from the coil pack? Also is it safe to run it for a week til I get the coil packs?

 

[JUST4FUN]

IIRC IN THE F150 there was a heater hose above # 4 that leaked/ driped
not shur on the expy