[THEFERMANATOR]

A tune-up is changing the fuel filter, putting in plugs(only use AC DELCO platinum or iridium's), and changing the wires if they look bad. Sounds like either you have a fuel pump getting weak, something in the fuel system bleeding pressure down, or the throttle body is getting gunked up with carbon. Also trucks prior to 03-04 had fuel pressure regualtor issues that would allow fuel pressure to bleed off through the vacuum line to the intake, and the gas would flood the engine out when you go to start it. Try turning the key on, wait 5 seconds, shut it off, then turn it back on and start it. This will tell you if it is a problem with fuel pressure bleeding down. Also look at the fuel rails and find the regualtor, unplug the vacuum line from it and see if it looks like gas is in it. If tehre are any signs of gas in the vacuum line, replace the regualtor(common problem and pretty cheap to fix).