My 98 Navigator has started missing really bad after leaving it at the Airport for a week. I ran my code scanner on it and it says #4 Coil Misfire / Malfunction.
So I repaired the leaking hose and replaced the coil.. Still missing.

I think that the screw on the coil is the ground and this could be causing problems because it's cross-threaded and fairly snug-

After replacing the coil it ran fine while still my garage and didnt trip any codes. I backed it up 10 feet and it started missing again?

I dont have $800 dollars to get this thing repaired right now..

Any suggestions?

JP

 

Check the wire contacts that tell the coil to fire, they could be corroded.

 

The screw on the coil has nothing whatsoever to do with it's electrical operation. The coil ground is supplied by the PCM . . every time it fires.

 

Really? Thats interesting..


So-

I had it running w/o pulling any codes and revving smoothly- then when I backed up it misfires again and shows Malfunction in the Primary/Secondary of coil #4.

Could it be a corroded connection? I corrected the leak .

Thanks!

JP

 

Has it been hit on the right front ?I had an 02 crown vic hit pretty hard on the right front .Chased the problem for two days and finally discovered a short in the no. 4 coil harness a few inches from the plug.Did you check the spark plug?

 

The truck has never been wrecked. I did replace the coil and the sparkplug.
A mechanic friend of mine took a electrical tester ( Small light with + / - ) and hooked into the harness going to coil #4. While running the light lit.

So that tells me that it's getting it's signal.. However, it may not have a good connection to the coil. I think I'll have someone replace the pigtail to the coil.

Because the truck ran fine a couple weeks ago after tightning the coil nut down.. But started misfiring after backing it out of my shop so it seems something is still "loose"

Thanks!!!!!

JP

 

At my friends shop the other day a Ford truck came in that the dealer couldnt fix.They found it in 5 mins.A wire going to coil was broken!You might try piercing the wire with a tester.I dont remember exactly how they found it, but i believe they had a tester of some sort with the sharp point on the leads.