Pmoon

I have had my truck (05 5.4) for about a month now and it seems like every time we have wet weather it developes a misfire like it has water in the fuel line and lights the check engine light. This morning after last nights rain storm did the same thing! Any one else ever have this? Any Ideas?

eej711

Might be the sparkplugs, may need new ones. You may also want to seafoam your truck too to clean it out since I'm assuming it has a good bit of mileage since its an 05.

s_vares

Water may be getting into your fuel pump driver.
Check your trouble codes and report back

redrider911

Or drop the spare tire and inspect the back of your fuel pump driver for cracks.

Pmoon

Ok, I wouldn't say my fuel pump driver is cracked, I would have to say it is broken! the Aluminum housing is broke in two! guess I will start there!
Is that big cylindrical unit above the spare tire housing my fuel pump?

06F150CFCT

Just had your same problem Pmoon and I swapped out the FPDM on my truck and bingo! all fixed. Hope this is the same with you. It will be a big relief when/if that corrects the issue.

allinon72

It is absolutely imperative that everyone checks their driver module FIRST before replacing anything else.

Pmoon

This must be related, after having the truck for a week I brought it to the car wash and as soon as the under carriage wash started the engine died. After trying to start it till the battery was drained I had it brought to my favorite shop (Acme Tire & Auto in Rockford, Mi. go Alex!) and after checking it over found that my fuel pump inertia switch had been tripped so they reset it and told me that when the car wash grabbed the wheel it must have tripped the switch, but, it was the kind of wash that you drive into, no hook on the wheel. Could the FPDM shorting out have tripped the inertia switch? Or maybe when it went onto the flatbed?

theduke308

Sounds to me like your mechanic was giving you the run around. Chances are it was your FPDM and after it sat at his shop and dried is why it started working again. I would bet the switch under the fuse box had absolutely nothing wrong there.

redrider911

Luckly mine failed in my driveway. I drove an hour in the pouring rain the night before without a hiccup. Went to start it in the morning and nothing. First thing I did was take the gas cap off, turn the key and listen for the pump, nothing. Dropped the spare and took out 1 bolt on the module and it crumpled in my hands.

There is a new updated part, if you didn't know. It comes with new studs with spacers to keep it off the frame. They also sell the original part so make sure you ask for the updated on with the spacers. If you are going to the dealer, call around. I got prices of $100-135 from different dealers.