zackmetz

I have a 2007 bmw 550i 6 speed. When I come to a complete stop, a long stop like a red light, the rpms will drop down below 400. Then, to prevent itself from stalling, the rpms shoot back up to around 1000, and then settle around 600-700 rpms.

Once this happens, the exhaust note completely changes, accelerating becomes inconsistent, throttle response is terrible, and pulling out and shifting gears is a nightmare.

once I restart the vehicle, everything is back to normal and it runs perfect.

Vehicle currently has rich codes. I had my guy look at it and he has no idea.. cleaned maf, cleaned throttle body, and did a new air filter but nothing changed it. Vehicle currently has a custom dual exhaust (after cats and sensors). Basically a dual inlet/ dual outlet single chamber muffler under the trans, and then dual the rest of the way back (2.5 inch so it’s nothing crazy)

ive seen other people with similar issues, but it’s hard to find info on a manual 550, plus no one else mentioned how it goes away once you restart the car.

Any help would be much appreciated! I don’t always have time to restart the car at the red light, so I’m stuck driving it while it runs funny and I can’t see that being good for the engine. Some possibilities that I am thinking are:

failing 02 sensor
failing maf
electronic throttle issue/ tps issue
maybe the exhaust?
Mayne that goofy hose that was attached to the factor rear muffler that I believed opened up the second exhaust exit?
Dealer reflash?

seanjordan20

Do Really there's nothing you can do unless it gives a hard code. What type of plugs do you have or coils

zackmetz

True, I can give that a try tomorrow, its just strange being so intermittent. And also obviously hard for the tech to replicate and diag.

Kinda like my ignition lock issue. But I’ll save that for another thread.

seanjordan20

I had the same thing for years. I think it just worked itself out with maintenance parts I replaced. It only happened to me when I would let it sit for a while as my car was never my daily driver.