Got an '84 4Runner with a 22R. Went to take it through emissions last week and it failed the CO (%). Should have been 1.20 or less, and it was around 2.2 for both high RPM and idle. The tech said it was running too rich.
Took it home and started playing around and found that, #1, I am getting hardly no vacuum at the distributer. #2, the PO has drilled out the plug for the mixture screw on the car. #3, I can't get the idle to drop below 1100 RPMs.

So, I check all the vacuum lines and replaced a few that looked bad, looked for other vacuum leaks (and found none). I reset the mixture screw based on the FSM (3 1/2 turns out) and tried to adjust the idle, but it still wouldn't go down. It would go up, but not down.

So now I'm stumped. Any suggestions?

Thanks