Perhaps this has already been discussed, but it seems to me that we should have a sticky with a prioritized list of the first things you should do when buying a Cherokee to make sure it keeps going from A to B, and that the very first thing on the list should be to replace the crankshaft position sensor with a new one from the dealership. These things can cause so many issues and erratic behavior and be such a pain, as well as leaving you stranded with no warning.

Seems to me that the first week you have your Cherokee you should just replace the god-forsaken thing so that you can rule it out of any other issues that come up, at least for a number of years.

Seriously, it seems like 30% of the OEM tech threads have a reference that the OP might have a bad CPS. Can't we all just agree to replace these right off the bat? I'm an IT Director, and we have a standard operating procedure when a computer screws up before we start tearing it down and replacing parts. Reboot it, then make sure it has all the Microsoft updates. This rules out a host of issues and makes any remaining troubleshooting far simpler.

 

you could say that for a few other sensors though too. the tps being one them. you could argue the same for the o2 sensor.

downloading windows updates is free maintenance and bears no cost unlike replacing sensors.

if money is no object then go ahead, replace the sensors and enjoy your xj.

 

There are 5 xj"s in my family(92,99,00,01 and 01). The has never been a CPS issue with any of them.

 

Replaced my cps but never have had o2 sensor issues lol

 

You also understand about new part infant mortality too, lol.
If the sensor that's currently installed is working fine, IMHO it's best to leave properly working parts alone rather than risk being "final test" for the new unit.
You may cause a new problem related to the replacement sensor, compounding the pain of troubleshooting the existing ones.

There doesn't appear to be an 'average lifetime' for the CPS...some fail young, others outlive the 4.0. Not like a hard drive where 5-6 years is average lifespan. I'm not sure where the "replace it" cut-off age or mileage would be?

 

How's that go? ...."If it ain't broke, Don't fix it!"

 

X2

Had my renix for quite awhile now. Never had any cps issues.
Some 4.0"s eat them. Some don't.

 

While most XJ owners will eventually change their crank sensor, WHEN they do that varies greatly. As mentioned, I've seen them go early and I've seen them go late, but I personally haven't seen any XJ go the lifetime of the vehicle, although I'm sure it has happened.

I keep a brand new MOPAR crank sensor in the back of my XJ. Never leave home without it!

 

X2. I do keep a brand new spare in the glove box for just in case.

 

Usually they don't leave you stranded, you just have to wait 15-20 minutes till it cools off. I got my NEW MOPAR crank sensor from flea bay for about 17$, and the seller had more in stock, might wanna see if you can score one and keep it around.

 

I know I would prefer being able to ask for free advice without being expected to blindly throw money at it first. Putting $100 towards a 30% chance to maybe have a bad cps makes no sense.

 

I've seen them go completely dead with no warning. Temp is not a ideal with some.

 

I agree. You should also replace the piston rings to ensure good compression so you don't have to test compression when you get a missfire....

Jump threw the hoops when they appear, no need to waste $$.

 

it went out on my brothers instantly and we never got it going again

i carry lots of spare parts it just makes sense

 

Ok then...keep one in your glove box. Next you can read the nightmare stories of installing them.