Liquid

I am a fairly versed backyard mechanic but this one has me stumped. here is the issue. I can start my comanche in the morning and everything will be great sometimes it has ideling issues, (fluctuating from 100--1500 and back down) but it always runs fine, the most I have tryed to take it is 20 miles since this started to happen but still more than enought to get the engine up to opperating temp... the problem arises after I shut it down. if I sty to start it again within easily 2-4 hours it will catch and fire for , all of 1-2 seconds then die, for say another second and fire again. this will reoccure as long as I have the started engaged or have my foot on the gas (in whitch case it will rev up for a second or so before dieing on me. I have gotten it to the point where if I hold my foor on the gas just right it will sometimes stop cutting out. and sometimes even idle when I take my foor off the gas but then it will die out again(from steady idle) withing say 2 minutes, and then start the whole fiasco over again. the kicker is if I don't touch a damn thing and come back in 2+ hours it will stat right up and run fine, drive fine... that is untill I shut it down. repeat. if anyone cam help me out I would be eaternally greatfull. I just don't have the money to take it to a mechanic.