What causes the engine to surge & move the car while at a stop w/foot on break. on 1994 Ford Thunderbird

Had a multipoint check done12/11/12.Found EGR-No Flow Detected.Could this be the cause? The surging is getting worse over the last few months. Need to fix problem.
Had the Idle Air Control Valve replaced in 1995 w/20K miles.It caused a serious lurch at a stop!

Asked by for the 1994 Ford Thunderbird
poss bad iac sensor or vac leak.
1 more answer
poss bad iac sensor or vac leak.