Sometimes surges other times smooth at idle

[mjposner]

I am in West Palm/Wellington.

[ForcedFirebird]

Risky, I have stock headers, so not clear if that would still apply.

Where in SFL are you? Can always come by the shop for a diagnostic.

[mjposner]

Risky, I have stock headers, so not clear if that would still apply.

[MrBurgundy]

get a smoke test done to verify that there are in fact no vacuum leaks

[riskybiz86]

Had a similar issues and it was the placement of the O2 sensor. I have long pipe headers and the sensor is only embedded in one of the two exhaust pipes,causing it to surge.

I unplugged the sensor and it revs much higher at idle but it's stable. So eventually going to pick a better spot for it.

Hope that helps a little.

[mjposner]

My 325i will sometimes surge between 600-700 rpm at idle, cold or hot, and other times stay steady at 700 rpm. With a/c on same issue, though now 700-800 rpm.


ICV was removed and cleaned (though not dirty). No obvious vacuum leaks though all rubber is original. Fuel pump is also original.

Thoughts