my first question is do vac leaks cause only a high idle, or can they cause low ones as well?

my second question is would the tps being out of range, cause low speed jerking with throttle input and a low, searching idle? and what should the tps voltage be at idle. i have a pfc, so i can just look the sensor in the etc. menu

 

also while playing around with the functions, i turned off o2 feedback and the surging idle stopped, though it still did it while coming to a stop in neurtral or with the clutch in. i thought you are supposed to leave o2 feedback on as long as you have emissions stuff like the air pump. is this true, and what effect does it have on idle.

and the car only surges when the car is fully warmed up. when i first start it, it holds a steady idle and vacuum

 

i checked the tps sensors using the pfc commander, the voltages are about where they should be
vta1: .43 closed
4.33 open
vta2: .96 closed
4.97 open

which about about spot on.
next im gonna test the isc b/c when i disconnected it before, the revs did not shoot up high, as i have read it is supposed to. the tone of the car lowered as well as the loudness and instead of the idle fluctuating high, it did it really low from 500-800rpms.
any other suggestions?