perryjr84

2007 FX4 5.4 FLEX

Hello all,
For a few months I've been experiencing the typical shutter at 45-50 mph while under load. While this has been happening i assumed it was fouling plugs/coils on a truck that just turned 100K last week, and during this time i have never had the check engine light come on even once.

However twice this morning i experienced more severe shuttering that occurred outside the typical 45 mph range, and eventually lead to a total shut down. Once it shut down it would restart at a VERY rough idle (think it was under 400 RPM) and shut down completely after giving it gas.

So after having it towed home, I tried the following. It seems to be running better than it has in months, but i really don't think i did anything significant to lead to the repair and just want opinions before i try to drive it any real distance.

Once I got home here is what I did:
1. I had been planning on replacing plugs soon anyway, so i removed all the coils and tested them with an ohmmeter. Across the primary terminals all of them tested at .6 ohms. Across one of the primary and the boot end they all tested the same as well (about 540 on the 20K scale)

2. Once coils were removed I sprayed Freeze-Off into the plug cylinders in preparation to remove (but i did not loosen yet)

3. I removed the boots (which were fine) and springs from the coil packs, and gently cleaned the terminals. Applied grease to everything before putting back together

4. While the plugs were soaking i attempted to listen for the fuel pump, which i did not hear. I then inspected the FPDM and did find that it was corroded to the point that it had broken in half. I removed it, pieced it back together for now and reattached it.

5. Just for shots and googles i reattached the coils, knowing that i wasn't attempting plug change until tomorrow.

After all this i was not surprised to find that the truck would not start. I disconnected the battery for 20 minutes, then reattached and the truck fired right up?! And like I said it is running perfectly. Does anyone have any clue or is this just really dumb luck?

Thanks,
Perry

bourgeois1269

I think you found your own problem when pieced your FPDM back together. Get another one their about $60+ on eBay and if you don't want to wait then call around to different auto stores and find out who had the cheaper "Dorman" FPDM

Mod (Ret.)

That also could be an unmetered air leak. If air is getting into the intake after the air sensor, this can cause the PCM/ECU to be off in its air/fuel mapping.

When you changed the plugs, could you have forgotten (on the first round) to tighten a clamp for any of the air intake tubes or air filter box on reassembly?

perryjr84

Thank you for the response. After thinking about it further, I didn't even think to consider the relevancy of the weather when I was driving yesterday. I was driving through very thick fog when most of my symptoms occurred. Based on the state of the my module above I would concur the moisture definitely lead to temporarily shorting out my module.

Thanks and good luck to all

perryjr84

Thanks Bucko......I just saw your response. That is good advice, however I never changed the plugs. I merely began soaking them in prep for changing them today.
But much appreciated! Thx and have a great weekend

techrep

iTrader: (1)

Yeah... that FPDM is your problem...plugs are due also...

Mod (Ret.)

I'm so glad I live in the south!

How this truck even ran at all with that FPDM module in that condition is simply a miracle.

perryjr84

Actually it stalled again in my while turning out of my driveway. Now I recorded sound of my throttle body with key on/not running and it doesn't sound healthy at all lol. Gonna clean the hell out of it and see if that helps before I try to drive and get codes pulled. I can think of a better way to get the day off from work!