bazball99

I have 2004 Fx4 with 225,000 miles. It's been a GREAT truck!! I've been following the bucking / jerking / misfiring a lot of people are having. Through researching and trail and error, I've narrowed the problem down to the COP (coils). "SeaFoamed" the vacuum lines, ran SeaFoam through the gas tank, cleaned the MAF, replaced fuel filter, replaced air filter cleaned the throttle body and I replaced the plugs about 20,000 miles ago and the bucking problem seemed to go away then, or at least significantly reduced it. Lately, it's been MUCH worse. I'm still on the factory coils and NO codes are making the check engine light come on.

Here's my question.....

Do I have to replace the entire coil, or can I just replace the spring and boot on all 8? I don't want to have to buy 8 coils if it's just the boots and springs. I've read several places that since no codes are being triggered, that the coils are doing their jobs and the problem is in the boots / springs.

Thanks for any advice...just trying to save some money.

Batten

Just fixed this issue myself yesterday by replacing all my ignition coils. If you bring it to a shop they can run a cylinder contribution test to find out which ones are bad. I also had no check engine light even though two were bad.

lewissa81

I would replace the boots first. You can get all 8 for about $30 from Rockauto. Also clean the corrosion off of the COP contacts, and put some dialectric grease where the spring meets the plugs and COP contacts. This should be done whenever plugs are replaced, in my opinion.

VTX1800N1

Ford Vehicles With Hard To Diagnose Misfires: Why…:

bazball99

UPDATE: I disconnected the battery and then pulled the coils off. I cleaned the springs and scraped off any corrosion on the the little tab on the coil itself where the spring connects. I used some electrical cleaner on the tabs, springs and the electrical connections. I used some dialectric grease on both ends of the springs, as recommended by lewissa81. I also blew out the plug holes with an air hose to clean out any debris and to clean off the top of the plugs a bit. So far, it's been running like a dream and not one misfire (or buck)...although I've only gone a few days on it. I will keep you guys updated.

FStorm150

Good to hear. Most times like you said it's just the boots and springs that either need maintenance or need to be changed. I just recently had the same problem, however I replaced plugs and boots at the same time. At the time my plugs were only 30K miles old so I thought no way could it be them, but I didn't know what else to try before spending an *** load. Maybe the plugs were still good and it was just the boots that needed to be changed, I don't know. Bottom line is the problem is fixed now.

lewissa81

Good to hear. Let's hope she stays running like a champ!

dmontelongo

Just replaced my coils tonight and fixed it. Wish I found this post sooner and it may have saved me some money.