aux fan + low idle = vibration

[colo525i]

I'm a new owner of a 92 525i. In the past few weeks i've been replacing broken/worn parts. The car had a bit of an idle shake, so i did the motor mounts, idle shake is now gone. Also did the aux fan as the old one was seized. Now when the a/c is running at idle there is a new lower frequency vibration through the wheel. It is only when the aux fan is running (i jumped it to test while the a/c was off) If i ease the gas in to raise the idle to about 750 or so the vibration is much less.

I have also noticed rips in the air mass meter boot, and have ordered a new one. The current one is sealed with duct tape (ghetto i know, but better than unfiltered air) I am planning on cleaning out the ICV as soon as i get the new air mass boot. No CEL or anything of the sort. Anything else i should check?

[winfred]

id get the air leaks worked out then see where it stands, under 750 rpm?! in gear or neutral/park, under 750 in neutral/park is too low which means somethings not jiving right

[ThoreauHD]

First, fill out your profile. O2 sensors would be another thing to look at.

[Jon K]

If you end up needing an aux fan I have one from a 92 525