Engine stalls on 1997 Ford Expedition

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

3 answers
check for vacuum leaks,mainly the pcv tube behind the throttle body.very common!
Yes and rpm runs high and low ?
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