[g2racer]

So... this happened today:

https://www.dropbox.com/s/mfdzn3un7f..._9821.MOV?dl=0

Out of nowhere, my 435i began lurching forward this afternoon. (This video is after I got home and finally stopped. Sorry for my “awesome” commentary... I was just shocked at this!)

It started accelerating erratically for about 2 minutes, as I was nearing my home. It was never wide open throttle — the sensation was as if I were left-foot braking, while holding the gas pedal down. You can see how it is almost cycling the revs. Took her to BMW tonight, showed three different techs the video, and NONE of them had a clue, or had ever seen this before... even my service advisor.

A few things to note:
- Car was in Comfort mode, regular “D” drive
- Fully warmed up, and had already driven some 5-7 miles prior to
- No CEL or iDrive warnings of any kind
- Brakes continued to work, no vacuum loss while this was happening
- Recently rained, but no standing water or puddles around/driven through

Okay, any ideas as to what the heck is going on?

The floor is open.

[Rebound]

Originally Posted by g2racer

So... this happened today:

https://www.dropbox.com/s/mfdzn3un7f..._9821.MOV?dl=0

Out of nowhere, my 435i began lurching forward this afternoon. (This video is after I got home and finally stopped. Sorry for my “awesome” commentary... I was just shocked at this!)

It started accelerating erratically for about 2 minutes, as I was nearing my home. It was never wide open throttle — the sensation was as if I were left-foot braking, while holding the gas pedal down. You can see how it is almost cycling the revs. Took her to BMW tonight, showed three different techs the video, and NONE of them had a clue, or had ever seen this before... even my service advisor.

A few things to note:
- Car was in Comfort mode, regular “D” drive
- Fully warmed up, and had already driven some 5-7 miles prior to
- No CEL or iDrive warnings of any kind
- Brakes continued to work, no vacuum loss while this was happening
- Recently rained, but no standing water or puddles around/driven through

Okay, any ideas as to what the heck is going on?

The floor is open.

Just a wild guess... maybe the PCV? My understanding is that when they go bad, it will cause uneven idle. I don't know about lurching, but is your idle steady?

BMW integrates the PCV valve into the valve cover, but there are third party solutions to cut the old valve off and replace it.