a bad brake booster doesn't cause the car to stall.

could be a vaccum leak, incorrect ignition timming, bad ground wire, clogged fuel filter, bad gas, incorrect gap on the spark plugs, ect.

you could also try this:
http://www.cb7tuner.com/vbb/showthre...&highlight=iac
http://www.cb7tuner.com/vbb/showthread.php?t=49352

that may help your up and down idle. later.