2001 325Ci Idle issue

[franikk]

I noticed on my way home today that when I was approaching a Red-Light and pushed the clutch in and the RPMs fell; the idle would fluctuate between 700 and 2200 RPM. It felt like it was goin gto cut out so I had to hold a higher RPM.

Driving wasn't an issue - ran fine, until the second Red-Light! The RPM's fluctuated and then cut off. Cranked it over real quick and drove off. Third Red-Light everything was normal. Pulling into the driveway, fluctuating RPM's! Stopped the car to get the mail and it idled smoothly.

The only recent thing I have done was replace the alternator yesterday and it ran smooth this morning going to work.

I am thinking that it could be bad gas maybe as I just filled up this morning. I am at 148,000 miles

[Jack Dabsy]

Hmmm, I am steering towards either a dirty MAF or Throttle-Body at this stage...
But, your Battery will have been disconnected to install the new Alternator and the result could be that the ECU has reset to default values and is learning all-over again !
Could be a combination of the above, mate... Just a thought !

[franikk]

Originally Posted by Dabsy

Hmmm, I am steering towards either a dirty MAF or Throttle-Body at this stage...
But, your Battery will have been disconnected to install the new Alternator and the result could be that the ECU has reset to default values and is learning all-over again !
Could be a combination of the above, mate... Just a thought !

Thanks Dabsy, yes the battery was disconnected and in the back of my head I did consider this. There was no reset of anything except the clock. It acted better today, so who knows. Someone mentioned the ICV.

[Jack Dabsy]

Idle Control Valve fault would cause this too, might be an idea to clean all three then you will have peace of mind that they're fine!