Engine stalls on 1997 Ford Expedition

Ee. Engine stalls at red lights rpm ramps up and down ???

Asked by for the 1997 Ford Expedition
check for vacuum leaks,mainly the pcv tube behind the throttle body.very common!
2 more answers
change the grade of fuel for 1 cycle and run a can seafoam, the computer is having mixed signals from the fuel relay system. which in turns needs to be kicked back in by using a higher grade of fuel and try using a name brand station. Find one that is always busy where the fuel doesn't sit
Yes and rpm runs high and low ?