I have a 01 XJ with approx 250k miles... all in all it runs pretty well.. good compression, good power, and no real issues... anymore

HOWEVER, when it get's hot and is turned off it is sometimes hard to start - it turns over forever but will not start. Then once you cycle the key off and back on it fires right up with no issues.
Oh and there is the occasional misfire when it's hot but nothing that's super noticeable.
Fuel pump??
IAC?

Normally I'd test the pressure at the rail but it's so random I'd have to stop and hook it up everytime I shut it off.. haha.

 

It sounds like the the fuel pump or the filter/fuel pressure regulator is going bad .

 

when the crank sensor starts playing up it don't like heat I have heard of people hosing them down to cool it off to get a start

 

What you're getting is heat soak of the fuel rail. The fuel in the rail boils from the heat given off by the exhaust header after you shut it off. My 2000 WJ was recalled for a heat shield over the top of the intake manifold and all it is is an aluminum foil blanket that sits on top of the manifold and covers the gaps around the injectors where the heat of the cast iron exhaust manifolds can come up around the intake runners. Although your steel header isn't so bad in that respect, you can try a blanket of some sort to do the same thing.

 

I thought about heat boil/vapor lock too. Just kinda dismissed it due to the fact it started right back up. I’ll wrap it in foil today to see what that does.
Thanks for the help guys

 

I have the same issue, as well. I wrapped my rail and injectors, still the same issue. I am about to replace the pump, its old, and I suspect I may be getting hot and not working properly.

 

The fuel pump in my 2000 WJ has 252K miles on it and still delivers rated fuel pressure. I've changed the filter several times in the time I've owned it because it's in the fuel line separate from the pump module and easy. However the pressure regulator is in the filter so that might have something to do with it.

 

IAC and CPS are prime candidates. I wouldn't jump right to the fuel pump - mainly because it does not experience motor related temperature the way those do, and your information implies that it is working properly otherwise.

On your next hard start, try feathering the gas pedal a little while you start. If it starts faster - that is a clue that the IAC is not opening properly during startup. A throttle position sensor (TPS) that thinks the throttle is partially applied can also cause the IAC not to open properly. The TPS position can be checked with any OBD2 scanner, so that one is pretty easy to see if something is out of wack. On a 96, the TPS sits at about 16.5% with foot off of the pedal. It could be a little different on different/newer years.

I would also do a quick spark check during a hard start. Because if spark is absent, that will point more towards the CPS and/or ignition coil not liking the heat. That heat is pretty intense right after a hot shutdown.

 

I have an 01 TJ that acts like this. I removed the rubber seal ( on the cowl) that that the rear of the hood sits on and it mostly solved it. I have a 99 XJ that behaves like the OP talks about, once the XJ starts (second or third try) it runs perfect, no sputtering like the TJ. The rubber seal on the XJ is glued in so I have not removed it. If I open the hood (allowing it to cool faster) will start like normal much quicker that if I leave the hood down.

I had starting issues on the TJ years ago and changed the crank and cam position sensor and fixed that. These starting issues were random and didn't seem to be heat related.

I also had the foil blanket fix done, I was told it was for falling leaves getting trapped and burning. That fix made the heat soak worse for me. I took the foil piece out.

I am still trying to chase down the XJ issue, I have read some people fix the issue by getting a new coil. There are write ups on relocating the coil so it isn't an issue in the future. I have also read there is issue with the fuel delivery. I haven't figure out my issue yet.

Neither Jeep runs hot.

 

In my opinion heat soak isn't a cause, it's a symptom.

The OP needs to check his fuel pressure at the schrader valve. Mine didn't want to start when starting the Jeep warmed up and would also chug and act like it wanted to cut off when sitting idle when warmed up. After replacing the whole fuel pump assembly, it idles smooth in all conditions and starts right up no matter if cold or warmed up.

I would go ahead and replace the whole assembly but that's just me.

 

In an 01 you definitely want to replace everything you even suspect is bad since you need to drop the tank to get at the fuel pump.
Considering that it's more likely to break something when disassembling component parts on the newer style fuel pump than not, and the added difficulty of having to drop the whole gas tank to gain access to it - I completely concur. IF (again, only IF) you need a new fuel pump, then replace the pump assembly with a new part by a reputable brand. Don't forget to get new tank straps if you get any rust where you live - you'll regret it if you don't.