woolybooger

My 2005 lariat 4x4 has 185000+ miles on it, a 100000 of which is on the motor
Recently, there has been a jumping when accelerating. I initially thought it was
Bad gas, but have ran a couple tanks through along with some chemical, so I don't think that's it. The other day I was towing my camper and it was terrible. So, under a load or going uphill, especially with the overdrive on makes it worse!
I also noticed if you get into overdrive at a slow speed, then accelerate somewhat rapidly, it'll do it. I recently changed the transmission filter and fluid, which didn't help. Any suggestions/ advice would be appreciated!

PerryB

My first suspicion would be the fuel filter, followed by the FPDM.

Mod (Ret.)

Could also be ignition...plugs and/or coils

techrep

iTrader: (1)

when was your last tune-up done ? plugs,boots and springs,fuel filter stuff like that. does the engine light flash when this is going on ? any stored DTC's

SCORGE

Sounds like a misfire

woolybooger

Finally got a chance to go by the parts store and have them put it on the computer. It read a code p0446 EVAP canister shut off valve faulty signal. Does that sound correct, like that would do it? Thanks again for all the advice!

Allinkdupp

Your p0446 code needs to be fixed but isn't your problem, that problem presents no noticeable effects to the driver.
Check your plugs, when my 04 did this it was because of the wrong brand of plugs.... Yes the 5.4 is that picky. Read this for your p0446.
The codes for misfire appear randomly.
Check cops and boots too.
Good luck

http://www.obd-codes.com/p0446

woolybooger

Allinkdupp, thanks for the info. Would not having a flap in the gas filler tube that closes it off cause the p0446 code? Also, I've noticed that my problem stops if I let off the accelerator and then get back on it. It is also intermittent.

Allinkdupp

I can't say for sure what's going on but I can tell you what happened with me.
I first noticed it while towing my camper then while accelerating especially up hill with no camper.
I could make it stop by letting off and driving easy.
I forgot the code but it was misfire cyl 3.
The only way I caught that code was with my tuner, it would go away when not misfiring.
I'm just offering my advise because it took me FOREVER to figure it out.
Changed to motorcraft plugs and all better.
Your problem sounds identical to mine except you have another code stored .
Maybe p0446 is a cheap fix? Maybe it will fix your issue.... Just wouldn't count on it.

woolybooger

I believe you're correct after reading your link. I had recall work done on motor at 88,000 miles due to injector problem. Also had plugs changed at that time. I have 185,000 on it now, so it's probably past time. Thanks again!