papa tiger

I think you really should center in on a vacuum leak diagnosis first thing. Then if you have no vacuum leak ( they can be very subtle ) ?

pattidrives

Papa,
I hope the service mechanic would have checked for a vacuum leak.

djfllmn

iTrader: (1)

not this BS again.....

foxkw

So My father was using 2004 f150 XLT 140K Mi, and rear ended someone while approaching a stop sign as a result of SUA. I remember the incidents with Audi's in the 70's or 80's with Audi's and they concluded Driver error; where driver error is defined as misapplication of the accelerator when intending to brake or pressing both simultaneously. Virtually all SUA incidents (other than Prius ) have been linked to driver error.

He said it happened again on Sunday 3/8/15.

I personally have experience with ford's (and GM's) stupid pedal placement in SUV's -- I have BIG (13 XXW) feet, and I actually got my right foot stuck on top of the accelerator and under the brake pedal, and drove a Ford Explorer through the front wall at the shop before I could shut it down (actually that insurance claim was the only profit Bob The Builder ever made at his shop, but that's another story...)


I was assuming driver error the same until I ran across this thread, since he insists he did nothing wrong. I'm going to dig into the vacuum leak hypothesis as I have a lot of experience with vacuum circuits from the 80's when I was building and modifying carburetors. Vacuum leaks can be a bugger to find. Intermittent ones more so.

I think an intermittent brake booster hose/connector vacuum leak could be the culprit, and probably the easiest way to find it is to spray a cat safe carb/TB cleaner concoction on the vacuum hose and it's connections while wiggling it around -- this ought to cause a stumble or surge. A leak down test on the brake booster would be a good idea. the problem with relying on codes is that it deemphasizes developing good troubleshooting and sleuthing skills

I also think that it's highly unlikely that an intermittent vacuum leak would throw a code because here's what's likely to happen: the brake booster is drawing vacuum from the manifold, so it's below the MAF and TB, so the mix will go lean, get picked up as such by the O2 sensors, at which point the computer is going to richen the mixture, producing more power causing the motor to surge if the vacuum leak remains open ( lets more air in.) These corrections would be well within the parameters of normal operation -- that is the leak is not massive so it won't be recognized as a error condition because they have to operate within a range of acceptable values or it would be throwing codes all the time. Being intermittent, it's not going to get flagged by the ECM as a long term lean out condition or it might just start re calibrating its long term trim.

It's been terribly cold up here this winter plus we bagged 10.5" snow last Thursday -- changes in environmental conditions like this (extreme heat, cold, humidity , dryness, or some combination ) affects the hoses and other components -- it could be that the environmental conditions are causing leaks which go away/reset aft the vehicle is shutdown and restarted.

I'll let you know what I find.

Mod (Ret.)

Old thread, but worth mentioning that unintentional acceleration is a serious issue, and should be resolved immediately.

I commend anyone for insisting that a manufacturer identify and correct any unintentional acceleration issue with a vehicle. Putting your families life (and others) at risk for something you have no control over needs to be identified and correct ASAP.

To anyone that accuses you of any attempted law suit fraud should be ignored.

foxkw

Agreed but Not the oldest I've seem in a forum... but this also come up on the first page of a Google search for 2004 Ford F150 unintended acceleration, so it's likely to live on forever.

I'll post what I find. I've solved some real buggers-of-a-problem(s) in the past that "experts" couldn't find after extensive troubleshooting because too many people only follow the book and quit when it's not there.

If I can replicate it reliably I'll video it.

spotking

My vehicle is acting just as Patti described. Low speed or braking 4 times while in the woods while cutting firewood (I assumed it was the floor mats--DUMB) Took the mats out--has done it three more times --once in my driveway while barely moving--once on the street where I live going 2-4 mph-- and finally just off my driveway while parking on some pine straw. The last instance was 2 days after having a new throttle body and reprogramming at a Ford dealership (very nice people who believed how serious this is) $725 repair plus rental car charges. They are going to take it back in tomorrow evening and re-investigate. I am still driving it-- have been back out in the woods again-- feels like Russian roulette not knowing when it may happen again. I have a wife and five young adult children --of course who aren't allowed to use the vehicle. Just as Patti described it is a sporadic event --dealt with by putting vehicle in neutral and cutting off engine. I hope a cure is in the near future. I had hoped to drive this vehicle for years as I otherwise really like it.

papa tiger

A tiniest vacuum leak on the 2009 + trucks will throw the trans temp gauge whacko, the idle will add several 100/1000 rpm's and then the puter will shut the truck down and you restart it with everything normal until it does it again. The temp gauge things is due to the cluster being in sync with the puter at the hip.

Toshbar

The solution to this is to cut off the right half of the brake pedal, forcing you to move your foot to the left so it doesn't catch the gas pedal.

ALL of the anecdotes in this thread are when the brake pedal is being pressed.

spotking

So the gas pedal is the one on the right--that is helpful--glad I came to the right site. Have had my license for 48 years now I can be a safer driver. Thanks!