My wife's 08 528I with 56k miles that was a cpo at 36k, maintained as scheduled and no abuse. Anyway, she said over the last month a total of 4 times that it has stalled on decel at red lights, starts right back up, but sometimes makes a serious noise and idles rough. This is after it has been running for 25-30 miles with a few stop and goes with 75% highway, seems to do it after exiting freeway at higher speeds. I'm certain that it's probably a sensor, injector, etc failing. I have driven it and it seems to run like it should, idles fine, shifts fine, no hesitation in either auto or manual sport. I Unfortunly have not experienced this myself and have been unable to reproduce, therefore, either will the stealership and with no codes and just out of warranty I neither have the time nor money to start throwing parts at it! We have all been there, I'm going to do the obvious in regards to pulling a plug and cleaning the induction system, checking for air leaks etc. Any help would be greatly appreciated, thanks in advance!

 

Problems at deceleration, rough idle and noise (most likely high pitch) are symptoms of problems with crankcase ventilation.
Check your crankcase vent valve (CCV) and the surrounding hoses.
At least that's where I would start. Good luck!

 

Thanks, I just ordered a set we will see if that does the trick!

 

Does anyone have the part number and a good source to buy it? I have looked and can't find it anywhere! Please help! Thx

 

Part number for what? CCV?
You should check the old one first to see if it is the problem. Otherwise just throwing new parts might end up being too expensive.

 

Find someone to read the fault codes.

 

You actually confused me when you mentioned CPO etc. Does your car have CPO? If so, then this should carry you a little past the 50k warranty. Has the actually Dealer checked for codes? If not, that might be a good start. If you have a code reader or if a parts store checked for codes then it's possible they couldn't see the code (s) that could be stored. I once would get a CEL but it would not stay on for long. AZ couldn't see the actual code but the dealer could. Also, if you have a good situation with your dealer, I would get it in quickly since it appears you are just out of warranty. Sometimes they will cover things for repetitive customers as good will, it's worth asking. But either way the diagnostics fee might be worth paying for before you just start to buy parts.

 

That's the problem, there are no codes and our stealership here sucks.

 

Renhalt - did the new CCV help? I have the exact problem (2008 528 E60 N52) and am stumped.

As you note, this is intermittent and sometimes runs like a champ, next day like a chump. This usually throws a CEL and OBDII codes for P0015 (Camshaft sensor, exhaust) and P0305 (Cylinder 5 Misfire Detected).

I swapped out the exhaust camshaft position sensor based on P0015, but no improvement.

I thought may have been related to the thermostat since the fan would run at 100% even on the highway a code P0597 (Thermostat Heater Control Circuit/Open). A new thermostat fixed that, but it still stalls on decelerating to a stop after a long highway drive.

Other options I am exploring are MAF cleaning, battery/alternator providing low voltage, and exhaust vanos - but none of these explain why this _only_ happens after a long highway run. I've spent hours scrubbing the boards (and google) with no good solution.

 

I will look in a while at the paperwork from the stealership, I don't remember off the top of my head what it was. But I do Remeber it was something that wasn't an obvious thing we or any DIY's would have thought of.