All right here are your answers, since I got the first one I won't answer it again, 5.0 engine, 301,000 miles, I have in the last three months changed the O2 sensor, tps sensor, plugs, wires, cap, rotor, engine temp sensor, oil, filter, fuel filter, replaced fuel pump in front tank and sock, with less than 3000 miles on all now. plugs are gapped to spec, no I don't press it unless if fails to start then I take it to the floor to clear the engine. I have had three mechs pull the codes and they have kept it for a few days, to no avail, the check engine light only comes on because the O2 sensor is reading rich, that is all they can get it to tell them.
EFIs don't flood. What are the exact symptoms you're seeing? What engine? How many miles? When was the last service, and what was done? How many miles on the fuel filter, plugs, wires, cap, rotor, air filter, & coil? Are the plugs gapped to the spec. on the emissions sticker under the hood? Do you ever press the gas pedal during cranking?