jking0385

I've seen several posts on this and i've tried pretty much all of the suggestions outside of transmission work. As the thread title suggest, it's the issue with what feels like a misfire when traveling between 40-50mph and when in O/D. If you try to accelerate the shudder feels worse until it drops into lower gear then it goes away.

I've owned the truck since it had 102k miles and it now has 132k and i've never changed the transmission fluid in it. The previous owner passed away and his wife had no idea what maintenance was performed on the truck. The fluid is pink so FWIW that appears to be normal but i've never done any kind of transmission work so i'm hesitant to go that route.

I have replaced all coils, plugs and now the fuel filter. Still seeing the same issue. I even removed all new coils and re-torqued the plugs to 25 ft lbs and there were a couple that appeared to have backed out. I hooked up my SCT tuner to a laptop and checked for misfires but it's not showing any misfires (type A or B). I did notice the Fuel pump driver module looked corroded and i ordered the part for this last night. Is there any chance that replacing this part will fix the issue or does the FPDM only prevent the truck from starting when it's bad?

I also plan on cleaning out the MAF sensor today to see if that helps as well. Only aftermarket parts i have is a Spectre CAI and SCT tuner with the basic tune that comes with the tuner itself.

Martian

Is it a shudder or a vibration? I wonder if it's your U joints or your parking brake shoes.

jking0385

More of a vibration, feels pretty close to a misfire

Martian

I'm hesitant to say it's a misfire if you've already done plug and coil work and you have no blinking check engine light. Have you done a scan for pending codes?

jking0385

No codes are shown from my tuner and i also had autozone/o'reily use their code scanners which come up empty. I'm really hoping it's the FPDM but i feel like i'm chasing the white whale at this point.

Martian

No codes... no flashing CEL... new plugs and coils... specific speed only... definitely thinking it is NOT a misfire.

f150fx4matt

Had the same exact issue with mine. I changed all the plugs, coils, and boots and the problem went away. Never once threw a CEL during that time.

jking0385

*update* replacing the Fuel Pump Driver Module seems to have resolved the issue (for now). The shudder/misfire doesn't occur when it's in overdrive between 40-50mph any longer.

Pics of old and new FPDM below

BadFish523

It was DUE! LOL glad you got it fixed. I suppose I'll add a shudder at speed to one of the many, many symptoms of a bad FPDM. These dang things cause some weird symptoms of a broad spectrum.

adanvjr

Is that the Dorman brand?

I haven't got underneath to check mines yet.