low speed surge
 

I've had a problem with my truck since new. When I drive about a mile, shut
it off for a few mins, then restart it and try to drive at a slow constant
parking lot speed it surges. I had the computer reflashed once and it went
away for a couple months, but returned. I took it to the dealer and in 3
days they were unable to duplicate it. It only happens when it's partially
warmed up and only if it's turned off, then restarted. I can easily drive
around it by letting off the gas, then gently accelerating again but it
does irritate me. Apparently no one else has experienced this that I can
see. Has anyone else experienced this? I have a 2004 Scab Lariat with
24000 miles.

When was it last reflashed? Maybe they have a better program if it's been awhile.

Yes, I have the exact same issue. Reflash helped then it returned at a later date. I have just lived with it. If I accelerate slightly, it will smooth out. But, it only does it occasionally and I have a hard time duplicating it myself. Mine is out of warranty now.

My truck had done it since new. Hasn't done it often and has never gotten worse.

It was reflashed probably a year and a half ago but when I had it in the shop
a couple of months ago the service guy said it had the latest update and
that they wouldn't reflash it if it has the latest update. I guess I'm not the
only one with this little glitch. It goes away in 30 seconds or so but it did
do it when I was driving about 20 mph leaving the base the other day.
Thanks for the response.

I have an 04 5.4 FX4 & I've had the same since new. I had the Ford program reflashed soon after getting the truck for other issues but no difference. I've run the superchips tune for 2 years - still happens... as you say, not easy to replicate... you just have to catch the right speed and then it oscillates up and down until you stop or accelerate.

Now 07 arriving in April - interesting to see if the quirk is still there.

Mine does that every now and then only when I first start it and in a parking lot going slow, when it does do this I accelerate slightly, it happens so rarely that to me it's not
a big deal.

mine only does it while in reverse. I just thought it was in my head, but I guess not. like everyone seems to point out, it only seems to do it while semi-warmed up. the motor will idle fine, then bog and suddenly spin up 100 rpm or so. very weird

at least it isn't doing what my old Taurus used to do. while idling through parking lots the car would goose the throttle enough to get a 1st to 2nd shift. scared the heck out of me a few times.

I had the same problem trying to drive out of a parking lots after going shopping. The only permanent solution I have found to date is to ditch the factory programming and install aftermarket tunes. The factory runs these engines too lean and that is why your getting the low speed surge, the engine is choking out, and then trying to catch up again. Just beware that if the dealer catches you with the aftermarket programming, they can decline your warranty.

Parking lots are primarily where I see it. I'm getting the feeling that lots of people have this problem and don't realize it. I'm quite sure Ford must know
about it. So I take it one of these Edge programmers would eliminate this?
I'm a little hesitant to mess with anything because other than this little
issue the truck runs great and is giving me mileage in the 17 mpg range.

mine does it too and i just ignore it kindof like the cam phaser knock. it doesn't get any worse so i don't worry about it, but thats just me.:-X21

I have a custom SCT tune on my truck and it still does this in parking lots, it does not bother me. I also have the cam phaser knock since brand new and it is not any louder,
the truck runs great and I have not had any problems, going on 35,000 miles.

I'm using the Diablo Sport Predator only because it was the recommended tuner when I bought my truck, before the Edge got all the press. I have had good luck with it so far but I also run it on the mid range , 91 octane setting. In addition, I've gone through and very slightly even tweaked those settings to what feels best for me from the drivers seat.

anyone considered a throttle position sensor? my ford doesn't do this but I had that sensor go out in my tahoe and that's kinda the way it acted. just a thought, sounds really common.