Sporadic Starting Issues

I have a 1990 Wrangler with a 2.5 liter motor and 5 speed tranny with 153k on it that I bought about 5 months ago. Lately it has been testing my patience by leaving me stranded in various places around town and home. It runs great when it wants to run but there are times where it will not start. It does not seem to matter if it is hot or cold or wet or dry out. Sometimes when I go to start it, it just turns but will not fire up. Give it 5 min. and it starts up like nothing is wrong, but then there are other times where you can spend 2 or 3 hours trying to start it before it will start. It does not do it everytime I try to start it though, I can drive it for 2 weeks and it starts up first try every time, then all of a sudden it wont start. :eek7: I have a fairly limited budget so I do not just want to go throwing money at it on a hunch. My first thought was maybe fuel pump since spark is good but dropping the tank and replacing it will make me :screwy: if that does not fix the problem. Some friends have mentioned the CPS but since the problem is so spradioc I really have my doubts about that too. It has only started doing this within the last couple of months but it has happened 5 or 6 different times within this time. Hopefully somebody can help me with this before I find a short bridge to send the jeep on a long drive off :frown:

CPS is a big issue on the 4.0 and can cause what you're describing. I've never done the job on the 2.5.

I don't know if that model year can give you any diagnostic codes...have you tried?