Wondering why my car won't stay idling when I go to start it up 50% of the time needle just drops and car shuts off

Sometimes when I go to start my car it won't start
the idle just drops in this case either hold on the
gas and keep the RPM's High and hold for a minute
or so let off.  Or put my rmps high and put car in
reverse stop then will work just fine. Other times it
starts right up. I replaced my map sensor,
serpentine belt, air filter, spark plugs wires,new
Catalytic  converter, battery. Car only does it every
so often but does it in warm weather or cold
weather it doesn't really matter when. I  have no
check engine light on. brought it to a few shops no
codes come up. Sensors  that needs to be fixed is
ABS Hub sensor and fuel sensor cuz my gas gauge
is off. Second owner car has 108,000 on it