MORI3L

As the title says.


My car has been sputtering for the last two weeks. I took it to Mckenna BMW and they couldn't diagnose the car. Apparently the car was not throwing any faults.

The sputter ONLY happens when the car is idling or is under 3K RPM. Anything higher and it isn't really feel-able. Also, after driving very aggressively on the highway, the sputter will become less pronounced if not disappear all together temporarily.

When the car sputters, the RPM's drop and then bounce back up to normal.

Its driving me nuts, i'm taking it to another mechanic to take a look at the engine tomorrow. Any help would be greatly appreciated.

Car is a 528i with 90K miles. I've done regular oil changes, did a tranny oil change recently, and only fill up with Cheveron/Shell.

tonyb635

Mine had a rough idle but only at startup and it was very short lived. No codes for a month and finally the CE light illuminated. I checked the codes and found one in the DME that pointed yo a misfire in #6 cyl. I changed my plugs and swapped #5 & #6 coil packs to see if it moved to #5. So far my issue is gone!

MORI3L

My mechanic is changing my spark plugs tomorrow and he's going to do a pressure test to see if my head gasket is leaking. Hopefully between those two we get some clues or it fixes it. If not, I guess i'll have to try replacing all coils.

BMW535xia

, possible injector problem

llcoolj0n

^ Leaky injector & dirty MAF sensor possibly....

MORI3L

The problem is 98% fixed(VERY VERY faint sputtering, you have to stare at the Tach to notice it and even then it barely happens). Replaced all spark plugs and coil on #1. The other 2% is probably from another coil on its way out. Will probably replace the other 5 in the next couple of months.

llcoolj0n

Awesome, glad you got it taken care of!

b00sted415

Throughout this whole process you never received a check engine light? When my check engine light came on, I took it to get read. Misfire #6 cylinder. After replacing the coil and spark plug check engine light went away. As as preventive measure I replaced the rest of the coil's including spark plugs.

MORI3L

The Check engine came on for about 30 seconds once and then disappeared(was accelerating hard on the freeway). The first indy I took the car to found a misfire on #1 code. He then decided to erase all the codes as there was several other codes present from when I swapped my battery(to see what code comes back). This probably hindered the dealer's ability to diagnose the car. However, since I remembered there was a fault on #1, I just replaced that coil and all the spark plugs. Problem solved(for now, heh).

Overall, it seems like the sputtering was not severe enough to throw a fault most of the time since I didn't get another fault after having cleared the original faults. I guessed right in this instance, so call me lucky.