I took my 2011 Lariat in for first service and reported that it sometimes tries to accelerate on its own during slowdown from high speed, eg when coming off a freeway ramp, rpms go up and vehicle wants to speed up rather than slow down. (sounds like something a Toyota would do!)

Dealer says its a known problem with 5.0L and performed a supposed fix per "TSB 11-8-9, 5.0L ENGINE BRAKING PERFORMANCE DURING LOW SPEED COAST DOWN," essentially a PCM reflash.

Questions:
Has anyone else noticed this problem?
Did the TSB fix resolve it?

Happened once in a parking lot...thought the floormat was stuck on the accelerator but the pedal was clear.

 

Must have something to do with that Ford/Toyota joint venture. I knew nothing good would come from that!!

 

Be aware that the engine rpm's go up because the transmission down shifts as part of the slowing down process. This can make it sound like the truck is speeding up when in fact it is slowing. Higher rpm's and sounds would naturally make someone thing they are going faster in some cases.

I discovered the same thing the first time I was driving with the cruise control on. While on the down side of a small hill the rpm's suddenly went up. It also sounded like I was going faster.

 

Maybe some people would have a perception problem, but Ford has acknowledged it as an issue with the 5.0L's and put out a TSB on it.

In my case, the speedometer changed to and was showing faster speed after braking to slow down, which is just not normal, in fact is dangerous.

In a parking lot looking for a space with your foot on the brake, vehicle shouldn't be fighting you to accelerate.

 

No problem here - 13,500 miles