A few months ago my 2005 5.4 started shaking pretty vilolently at about 45 mph. At consistent speeds or even WOT but below 45 it would be fine. I finally got it to throw a code which was p0308. My father being a mechanic suggested I change the coil as the plugs had been done recently. After changing the coil it was fine for a few weeks until the same problem and same code hit me. I took the coil out only to find moisture on that coil. not thinking and wanting to diagnose it. I switched the coil from 7 to 8 and 8 to 7 after drying off the coil. It was fine for another few weeks. Then it started happening again and it was still that p0308 code!! I checked the coil and there was moisture. So after drying it and pounding my head against the wall. I found some dialectric grease and put that on the boot, and it was for a couple of months!! Now the problem is happening again. Same code. What's the deal. Is it possible that coil is breaking down now? I have also read somehing on a problem exactly the same as mine being fixed with the fuel pump driver module. It does have 130k on it and I live in the north where salt is thrown everywhere in the winter. But would this give me a misfire code? I'm low on funds and would rather not fix things that need not be fixed right way!

If anyone has any bit of help, please respond!

God bless!

 

1. Use only quality COP's - Motorcraft or Visteon

2. Apply Dielectric properly: https://www.f150online.com/forums/20...ml#post5128817

3. Given it's a 2005 3V, It may be prudent to heed this if misfires persist: http://ww2.justanswer.com/uploads/sd...229_r07m08.pdf

What's the source of that moisture?

BTW - if it's persistently the same cylinder, it's unlikely it's the FPDM. However, it's is ALWAYS a good idea to keep an eye on the booger - refer to: https://www.f150online.com/forums/ar...placement.html

good luck
MGD

 

No clue where the moisture is coming from. do you think that's the culprit? Also are we ruling out the FPDM?

 

Howdy.

Moisture and ignition do not mix. If the proper application of dielectric and high quality parts don't fix it, it's time to track down the excess moisture source. Once that is solved, and it STILL misfires you'll need to go deeper. - injectors, PCM drivers, cam followers, etc. Even a faulty plug - it does happen.

As fer FPDM - I addressed that in my previous post's revision.

MGD

 

It's just so odd that it only does it so rarely.

 

Whatever you do, be proactive, not reactive. Unaddressed misfires will eventually damage yer engine, cats, and O2's. And leaking injectors can potentially hydrolock yer engine and destroy it outright.

Inspect and replace as discussed. Don't delay.

MGD

 

Id inspect the cowl seal. The likely source of moisture for that plug hole..