starting problem

i have a 1994 cherokee country with 2.5. I'm having a starting problem. In the morning my jeep starts up right away no problem. The problem happens after its warmed up. After its been warmed up and i run into a store for five minutes, then come back out to start it, it won't startit just keeps cranking, but once i put the pedal to the floor it starts right up. Everytime i drive around and run into a store and i need to start my jeep I have to put the pedal to the floor. can someone please help me out.

I'd probably first check the TPS, IAC, and throttle body. Good luck.