Herkguy

Have a 2011 Ecoboost with 11k on it. 33inch tires and a level lift. Anyway, since I've had the truck it has gotten 14mpg which I figured was ok due to the lift/tires. But it also idled very rough and seemed to fight me when coming to a stop and in traffic (like it wouldn't downshift fast enough or something) Anyway, took it to dealership with said symptoms and they couldn't find anything and chalked it up to the big tires.

Fast forward a month and I started it to go to work and the check engine light came on. Codes were P0630, something about a VIN mismatch, and U0422 another weird computer code. Well the dealership accused me of having a custom tune, which I feigned ignorance on since I didn't have one anyway. Cleared the codes, reflashed the PCM and called me to come pick it up. Started it to leave the dealership and the light was back on!

Anyway, a weekend of troubleshooting later they decided to replace the PCM. Once they did that they had a hell of a time getting the new computer to take the VIN number, but once they did the light went off and I was good to go.

So I figured this was a stupid computer issue, but was very pleasantly surprised that the rough idle was totally gone and I was now getting around 16mpg!

Long story short, had a rough idle, got a check engine light for a seemingly unrelated issue, got a new computer, rough idle gone! May be worth a try if you can convince your dealer to try it.

fatmikeboost

I have the same rough idle issue same truck with 25000 kms on it. I brought it in and the dealer changed a PCM module and a new flash. A few weeks later and the rough idle is back sometimes worse than I remember it. Any one else have any ideas of what it could be?

avvblanc01

Im having a similar rough idle on cold starts as well as the truck pushing when I stop. Ill mention this fix to the dealer when I go in for my 15k service.
on a side note I always feel like they're too quick to blame EVERYTHING on aftermarket wheels hahaha seat squeaks? lights out? must be the tires

caperJ

Maybe unrelated as I do not know but there have been reports of vacuum hoses being loose or off resulting in low mileage. Could this have an impact as well on rough idle. Dealerships sometimes overlook the obvious.

JaysonsF150

Yes and that was actually the issue I had with mine not that long ago, vacuum line came off the throttle body and messed with the brake system and the idle, cheap hose clamp fixed it

caperJ

Jason where are you in Calgary there are 2 of us from MacKenzie towne that I know of and 1 in MacKenzie

JaysonsF150

I was in Citadel until recently now I'm in Irricana, I've net a few people from Calgary but none from the forum

caperJ

There are quite a few people from calgary and close areas in the form and probably even some from Irricana

JaysonsF150

Quite possibly, I followed the Calgary thread on here when I first joined the forum but it was fairly dead so I gave up on it. Would be nice to meet more people locally and see what they've done and plan to do to their trucks

TwinTurboFx4

Decided to plug in my livernois tuner to check for codes and I as well had the U0422 code. I dont have any issue with my truck, it runs like a beast! So I have no idea what it means.