wont start when warm

my 97 f-150 starts up every time.........the first time. after i drive for awhile and shut it off it gives me a hard time starting. it just cranks over but wont start. if i give it gas it catches and tries to start but dies out right away after i let go of the key. sometimes after up to 10 tries and 20 minutes later it starts up again, so far! any ideas? also there is a gas smell, but im thinking thats because of putting the gas pedal to the floor. could it be plugs? i bought it with 180,000 miles on it. i pulled a plug and it does look pretty rough so i am going to change em tomorrow.
the parts store calls out iridium plugs. the guy told me any plugs will work. the only difference is the mileage you get out of em.
50,000 on regular plugs
100,000 on platinum
150,000 on iridium
not sure thats the case but i bought platinums. i had my 20.00 credit @ autozone so they only cost me 6 bucks :) seems like they are going to be a PITA to change. only on the 3rd one back and if feels like my socket wont drop onto the plug to remove it. rain stopped me for tonite.

My '96 was doing exactly what yours does until this morning. Mine has a 300 L6 & is closing on 285000 miles (!). This morning I changes the plugs & wires & now it starts up fine even after getting really warm. Hope you find success after changing all your plugs. I'd change the spark plug wires too with the miles yours has on it. I'm presuming mie plugs & wires were on the edge of being fine, but were getting just weak enough to not let the truck start when warmed up. Good luck!

changed the plugs and wires but still had to put the gas pedal to the floor to start it when i stopped for gas. runs wayyyyy better tho!

Check your air filter?

Pedal to the metal for starting is referred to as "clear flood" - throttle wide open, low vacuum lots of air. Could be dirty air filter - car is willing to start rich cold, not hot.

Other than that, might have to look for codes, although you want to get the plugs in first.

check o-ring on the fuel pressure regulator or the fuel pressure. if its not that, unplug the engine cooant temp sensor and see if it starts. toivo
also if your plug gap is too wide it will start hard, won't idle, die out, n act stupid. my car would start cold, but hard start, hot.o-ring on pressure regulator was bad.

OK mine did it again late last week. It hard-started, cranking slow like the timing is off, and then catching but not starting unless I babied it. It took about 15 tries to get it to stay running, and when it did I had to clear its throat a few times before it idled properly. This was 45 minutes after I changed the cap & rotor & went to pick up our dinner. I still had a miss that I thought would be cured by the new cap & rotor, but it didn't. Now I'll try and hunt down a vacuum leak - it stumbles intermittently at idle but seems OK under load or running down the road.