[William Miller]

I pulled the meter last week and found the adjustment screw. The cap was missing. The screw allows more or less air to bypass the flap in the air sensor.
Screwing it in closes the bypass and reduced the amount of un-metered air.
Unscrewing it allows more unmetered air which leans the mixture.

What I found was that the screw was backed out about 3 1/4 turns from all the way screwed down or closed.

I believe I'm lean because if I push the flap in momentarily the mixture richens up and idle is smoother. I then screwed the adjustment all the way in to richen up idle. It maybe helped a bit. After reading more on rennlist, I found info about "adaptation"

I want to reset the bypass screw to the base value and try the adaptation.

I think I read on the Carerra manual that when setting the co using the bypass screw you had to jump something out in a test plug to prevent the DME from making adjustments during CO adjustment.

I'm wondering if there is something simular on a 964 system.

My attempts are to get this back to factory default parameters and hopefully the hammer will help point something out.

Maybe I just need to try and figure out where the midpoint of that adjustment screw is in relation to the tube that bypasses the flap?