[bigds01]

Just had my mechanic go through and replace vacuum leak problem hoses, valve cover gasket and go through a new to me 2009 328i 136k mile car. There is now an interesting issue where it has an occasional rough idle at stop signs.

He also replaced a cat, one of the o2 sensors, crank position sensor, throttle sensor. The computer reader doesn't seem to find anything and the smoke test doesn't show any leaks. He is flummoxed as am I. Any thoughts? Good time to use fuel injector cleaner?

[lukasB]

yes injector cleaner is always a good idea and should be used regularly

[sea6speed]

Is the computer just not showing any codes or no misfires as well? You can have misfires and not throw a code.

[bigds01]

Originally Posted by sea6speed

Is the computer just not showing any codes or no misfires as well? You can have misfires and not throw a code.

Computer is throwing no codes. It just feels like an occasional misfire in gear at idle

[NFiftyWon]

It sounds like a misfire issue, but if you're not getting codes i would assume o2 sensor

[GRUESOM3]

Just had this issue on my 09 328i and it was a coilpack. No codes thrown as well.

[sea6speed]

I'd log misfires and see if they're primarily on one cylinder

[Just Plain John]

I had the same issue pop up on my car two weeks ago. Misfire #2 cylinder, but only when in gear, at a stop, with the A/C on. No codes were being thrown, but the scanner was catching it in the live data. I swapped in new plugs and coils and it's smooth as a baby's butt now.