2004 SCREW FX4. I have a miss on my #8 cylinder. The truck does have 99000 miles on it and is due for a plug change, but i figured that if the plugs were bad I would have a miss in another cylinder, which leads me to believe that the coil might be bad on #8??? Also i was driving home the other day doing about 75 MPH when the truck started to shake real bad with the check engine light flashing, felt as if I was having a blowout!! With money being tight I really dont want to have to buy plugs and coils! I'm gonna try the plugs on my own with the Lisle tool!!!

 

Hey,my 05 FX4 did the same thing last summer only it waited untill I was in a single lane on a major hi way I held up traffic for a mile.....anyway it cleared up on it's own,then just started missing again but not nearly as bad,it ended up being a bad coil on #6,it's been good ever since.

 

Yeah I was coming home at 2:00am on an interstate in the middle of no where! I'll try the coil, thanks!!

 

put a spark plug test light between you coil and spark plug, if you are getting spark then your plug is bad, if you are not getting spark your coil is bad.

 

I think it will be your coil since you are reading at the #8. I had multi misses and iford dealer couldn't tell me which cylinder it was. I did the plug job mysleft and I didn't break any. I will post the photos of my plugs. I used KANO KROIL www.kanolabs.com It took me about 10 hours to remove the plugs. I would come out every hour and turn the plugs 1/8 to a 1/4 turn or until I felt the plugs starting to creak then stop and let the oil penetrate the lower shield. Motorcraft pulgs at the dealer 20.00 a plug, the same plug at Adavance auto parts 7.99.

 

Where those oem from advanced?

 

Yes it's an OEM Motorcraft Platinum SP421. It replaced the PZT1F. If you do the job yourself make sure you put (anti seize) on the shield of the plug.

 

That's nickel anti-sieze !