will start sometimes , every time on ether.!

I have an 89 xj , 4.0l. I only use it for a woods rider. It will go anywhere i want and someplaces I would rather not. But only when it wants to start.
I have replaced the tps , checked the cps. cleaned and ops checked the idle air motor . check and replaced the map ,replaced the plugs , cap,rotor,and wires. new knock sensor (mine was busted off at the plug).sometimes she will start right up and run like a top , sometimes she will crank all day , shoot her with some ether and she will start, but will run at high idle around 2500 or 3000 rpm , sometimes will finally kick down sometimes not . It is very random , and is starting to make me mad , it is getting embarrassing when we stop to drink a few beers and she won't start to go hit a big hill . I have to screw with it half the time we all go out . other times she runs like she is brand new . she has 242000 miles on her, but i know she is still good for a few more and i really don't want to give up , sombody please help me!!!!
thanks

Power latch relay. If it goes bad, the IAC does not have time to retract so it is in the correct position for starting.

ok i can i just swap it out with one of the other two next to it , and the power latch relay is the middle one on the right fender well is that correct. thanks again