Why would my ford explorer engine rev up when at a stop?

Why would my ford explorer engine rev up when at a stop?

Air/vacuum leak in one of the vacuum lines, cracked or leaking engine head, honestly it could be a lot of things.

Yeah a vacuum leak is very possible. Get a can of carb cleaner, start vehicle, spray carb cleaner around every gasket, vacuum hose, and vacuum operated component. If the engine suddenly idles up, down, or it stalls you have found your leak.Repair as necessary.Another culprit on Fords is the iac(idle air control)valve bolted to the throttle body.Remove it from tb, disassemble it, clean the passages out with carb cleaner, move valve pintle back and forth and twist it also to dislodge any remaining carbon buildup.Blow it dry with an air compressor, reassemble, reinstall. Check the tps(throttle position sensor)voltage.Pierce the signal wire with the positive voltmeter probe and pierce the tps neg wire with the negative probe, turn key on/engine off.Voltage should be.95-.99volts, if not loosen the screws slightly and turn the tps sensor until you get it to match the correct voltage, retighten screws. Check the pcv valve and hoses for clogs and leaks. The maf sensor wires(inside housing)may be dirty