Just bought a 2000 jeep cherokee sport with a 4 inch bds lift, I have owned lifted trucks in the past but I have never done much with a jeep. The guy who owned it before me cut out the catalytic converter and ran an exhaust with thrush muffler and tip. I've heard that without a catalytic converter and no backpressure these jeeps will get horrible gas mileage, and also run like ****, would like to know if anyone out there can back this up. Any help would be much appreciated.thanks

 

In a 2000 you have 2 or 3 cats, and o2 sensors and not running a cat will throw off your sensor readings and cause problems. Is the cel on?

 

Yes it just came on actually, and the motor is running funny I'm hoping it's because of the exhaust

 

You should have the codes checked to give you an idea of the problem. You should put the exhaust back to stock, trying to remove/bypass that stuff will just cause more trouble and it's illegal

 

Do you have emissions tests in your state?

 

No there's no emissions tests here in michigan but yeah I just got it 3 days ago and the previous owner had all this exhaust crap on it, what it be best to just go to the junk yard and get a full stock exhaust?

 

Put the exhaust back to stock and run a nice flowmaster 44 on it. It will have a nice tone to it and be completely legal. You may want to upgrade the cats too while you're at it if you can. Check with your local laws to be sure on what you can and can't do. For me, I just need some sort of cat and muffler. I could literally hollow out my cat and muffler and get away with it since I don't get the little tailpipe sniffer. Not that I would ever do that, but technically I can. And NEVER mention anything like that on this forum, I just did for an example on my local laws. Talking about removing or hollowing out cats is extremely frowned upon on this forum and could get us shut down if it happens too much. Different states have different laws, including the federal government, so we have to abide by the rules of everyone. Welcome to the forum family, and keep the rules in mind!

 

Check and see what is there first you may just need the final cat, and you wouldn't want to throw on a clogged up jy on your xj and still have the same problem
Edit: how big are your tires? Has he speedo gear been changed to compensate?

 

Yeah I know about the whole catalytic converter regulations lol I just want to solve my gas mileage/ engine problems and I was hoping re doing the exhaust would help

 

You mentioned the lift, bigger tires? Did the previous owner adjust the speed for them?

 

Probably not he didn't seem too bright. I haven't dug much into jeep yet so I don't know how to tell

 

Besides pulling the speedo gear to check have a buddy in an unmodified vehicle cruise next to you at a constant speed and just cross reference the readings, the wrong gear will throw off the speedometer odometer and I believe some engine controls on a newer model like yours

 

I've yet to know anyone who removed a cat from a Cherokee who was happy with the result. These engines NEED backpressure.

 

:P