My car started suddenly started running rough with a low idle. I had to move the idle air bypass screw all the way out to keep it from stalling. Verified timing and dwell are within spec yesterday.

I'm wondering if the AAR is stuck closed, causing a rich condition. Consulting the PBanders D-jet bible, I saw this procedure for testing to see if the AAR is stuck closed:

Stuck closed: Poor running (low idle) after cold start. Check on cold engine by removing the input hose immediately after starting. If you do not feel suction, the regulator is stuck closed. See below for rebuild and rejuvenation procedures.

My question is, which one is the input hose? One hose goes to the cylinder head and the other to a nipple on the air cleaner.

Thanks!

That's not the AAR hose. You are playing with the antibackfire valve.

The AAR hoses come from the aircleaner and then to the plenum.

Thanks Ron.

Pulling the Air cleaner off made things clearer (I think). Am I correct in thinking that the "input" as described by PBanders is the hose on the right that connects to the air cleaner?

Click to view attachment

correct