The O2 sensor is BAD and needs to be replaced. Whats happening is when the engine is cold the sensor sends an air to fuel mixture signal to the computer that satisfys the engine's requirements at start, but when the engine heats up the sensor then send a leanner mixture (To much Fuel) that the engine can't burn off so the Sparkplugs get wet and misfire stalling the engine.
Fuel Pressure Regulator - would do that -
does my 1996 pontiac ga stall out in park
The thermostat control engine temperature. If it fails the engine can run hot or cold - that would happen long before over-heating caused the engine to stall.
Why would it stall or almost stall in Reverse but not in Drive? How long since it's received a tune-up and thorough check-up? How is the compression?
clutch
That would be a wing stall, or just, 'stall'. This kind of stall has nothing to do with the aircraft's engine, if it has one.
If you have a loose spark plug, your car will not stall unless maybe your engine has 3 cylinders. If you have a 6 or 8 cylinder engine you would just loose some power and your engine would run a little rough.
After replacing minor components that would cause the vehicle to stall such as the fuel filter. Advance the ignition timing a few degrees and the engine will run better and there will be no more stall.
if your fuel pressure is low it will also back fire and stall when it is warmed up. check fuel filter and fuel pressure. check with a scan tool and see what the temp sensor is reading (You cant do this by looking at the dash guage)
Driving through flood water would cause the ignition to fail and stall the engine.
Had a Jeep in the shop here with that problem last week and it turned out to be low fuel pressure. Try running a fuel pressure test. The Jeep would idle ok but when you tried to accelerate the engine would stall.
That would depend on what year of Ford Explorer and which engine you have ( my 1995 Ford Explorer with the 4.0 liter OHV , V6 engine has ( 2 oxygen sensors )