I bought a 1999 xj 2weeks ago.142,000 miles, good shape runs good.
I'm doing the standard maintenance and wondering do you recommend changing the cps,02 sensors and or tbs?
I am not having any issues with the vehicle, just want to make it right.

 

If it isn't broke, don't fix it. If it was me I'd leave that stuff alone unless you had problems with them.

 

I agree, if the gas mileage is normal and the XJ is running fine there's no sense in replacing what isn't broken.

 

Any idea how old the upstream o2 sensor is? That would be the only thing I would replace from that list if you have no record of how old it is.

 

I keep a new MOPAR crank sensor in the storage bin in the back of my XJ.

With an XJ, you just never know when it's going to go. It is possibly the most common engine management sensor failure on the Jeep 4.0

And because it is a critical sensor (it can leave you stranded), it isn't that unusual for some to change it as a preventive measure.

Please use MOPAR crank sensors for any replacement. Aftermarket crank sensors are "hit and miss" with a whole lot of miss. I won't use or will I recommend an aftermarket crank sensor.

 

Thanks for the replies. I'll leave some of it alone.
I have no idea how old the 02 sensors are. Bought it from a dealer.Carfax shows 3 owners, so who knows.
Tjwalker thanks for the heads up on the brand of crank sensor. I will be ordering one of these.

 

If you want a recommendation on oxygen sensors, NTK are your best bet. NTK (a subsidiary of NGK) was the original equipment supplier of oxygen sensors to Jeep when your 99 XJ was manufactured.

No better replacement sensor than NTK for a 99. I've replaced dozens of them. NEVER an issue with them.

You can get an NTK oxygen sensor aftermarket and save some money. It will be the same as the one you buy from a Jeep dealer, but will cost less. Check the online suppliers like RockAuto, etc. Napa I think carries them too.

 

I'll second that. It isn't a terribly fun job, even less fun if you have to do it again unexpectedly 2 months later.