Lowering ignition timing make car run like crap?
 

Curious as I just got my car back and he lowering the ignition timing because it was idiling high. Now everytime I come to a complete stop it cuts off then back on, plus it seems like its not running as good as it was before I took it in. Can the ignition timing take away from the performance of the car?

Ignition timing is not really the best parameter to adjust idle speed. The timing must be set to specification and then the idle speed is adjusted via the carbs or FI and the throttle linkage depending on the model of your car.

Does the engine cut off, drop to ~200 rpm and come back when lifting throttle from high rpm? Then it's running too rich.

I played around with my distributor when my car was suspected to be pinging, and don't remember idle rpm changing in relation to ignition timing. Lowering (retarding would be a better word?) the ignition advance makes the car completely powerless, i.e. you floor it but it just won't accerlerate. But I think running too rich could cause that too, due to incomplete combustion.

If he just lowered the idle speed by closing idle bypass valve (tightening the screw) then it must be running richer than before.

You need to find another mechanic.