It started at the beginning of the winter, like Novemberish. I came out to my 93 XJ after work one day and it just wouldn't start up. Crank, but no start. I came back the next day and it fired right up no problem. It's now March and ever since then it's just done the same thing randomly. Sometimes it will fire right up, other times it won't start at all... Then I'll come back 4 hours later and it fires right up no problem. What gives??? LOL

Anyways I missed a physical therapy appointment today after trying to get it to turn over for like 45 minutes so it's time to get this fixed. It's like some part is slowly dying. Do you guys think its the crankshaft position sensor? Is it worth replacing myself? How much would the normal repair cost be if I took it to a shop?

 

Crank sensor is a likely suspect, but it could be other things too. I assume you've checked for fuel and such. (hear the pump run?)
I had a shop change mine last time because it wasn't worth the hassle to DIY. Cost 1/2 hour of shop time, IIRC.

 

starter brushes, might tap with hammer, will go out sooner or later

 

OK here's an update... I replaced the crankshaft sensor this afternoon and it fired right up. I thought we were good to go. I go leave my buddies house 5 minutes later and then it doesn't start again! So i've replace the CPS (or CKS) and it's still randomly not starting. What else could it be??

 

Mine has done this for a lot of reasons. First it was a bad fuel pump and the fuel would drain back to the tank and not start right away, then the cps, now it's getting flooded for some reason and not starting. Could be injectors, could be the computer telling it to dump in fuel. There's lots of things it could be.

 

When I click the key over the aux position I can hear the fuel pump kick on (I'm assuming that's what that is) for 2 or 3 seconds, so I don't think its fuel related...

 

I could hear my pumps too, just can you hear them doesn't mean they're working. I can hear a water pump but it has a blown impeller. You can rent a fuel pressure gauge at autoparts stores to test it.

 

Test fuel pressure, test spark, test injector power, check codes. Could be anything from pcm issues to mechanical issues. Go down the list and check one off one by one. Thats what we call 'diagnosing the issue'. Much more cost effective than throwing parts at it.

 

Oh what does the exhaust smell like after it starts? Mine is really rich from the flooding of gas.

 

Next time it won't start, first thing I'd do is pull a plug and check for spark. Divide and conquer. If you have spark, check for fuel.
Offhand I'm suspicious of the coil as they get intermittent like that, but it could be 20 other things too.