[Natty_boh]

Hello fellow e46fantics,

Ok so I have searched every rough idle thread but can’t seem to find the same symptoms I am experiencing. My problem does not happen on cold start but happens when the car is warm about 10-15 miles of driving.
When coming to a stop, every time the car falls below 1000 rpm the rpm begins to fluctuate up and down between 1000-500. Eventually idling at 500 rpm, which is way too low. The car has stalled multiple times when the rpm drops to 300. The car has no vacuum leaks and is throwing no codes.

I have changed:
Spark plugs and coils
MAF sensor
Fuel pump and filter

Now from reading other threads it could be anywhere from:
VANOS seals
ICV
Intake boots
02 sensors
CPS sensors

If someone can guide me in the right direction before I tackle all these projects it would greatly be appreciated. As I am a college student so money is tight.

I have gone to 2 Indy shops and the BMW dealership and they keep telling me just to add fuel cleaner. :facepalm:

 

[choxor]

Codes?

 

[al0513]

happened to me today

 

[MadBMW]

Throwing no codes? wow. Most of the things you mentioned would throw codes if they had problems.

Check your DISA adjuster unit?

Had similar issues and it was a vacuum leak, 6th coil and cam shaft sensor that got me running again.

 

[DDNPresident]

Clean ICV?

 

[Teddy7]

Very odd you are getting no codes with these symptoms. My car acted almost exactly the same way as you are describing when I forgot to plug in the lower ICV plug after changing my CCV. Once I plugged it back in, it ran good as new.

 

[al0513]

Mine had no codes. I was stopped at a light , when it turned green, it stalled. Its an automatic. I put it in park. turned off the ignition and restarted it. No codes whatsoever. I'm changing out new belts today and I came upon a How to video on cleaning the IVC - Im thinking thats what it is. My car has 121K now. My commute is roughly 70 miles round trip each day.

 

[Natty_boh]

Update-
Changed intake CPS (had a code) and cleaned throttle body and ICV. Car idles normal but, rpm still fluctuates when under 1000. Car runs perfect, no loss power just annoying seeing the rpm go up and down. Any advice on what to do next?