I have a 99 Durango with an exhaust problem, my codes are telling me voltage issue with 02 sensors and i just replaced them both. Im going to check the connections tomorrow to make sure they are clean and secure but im pessimistic of this because i need to replace the actual muffler since it's got a hole in it and I'm wondering if i remove the cat also after replacing the muffler if that will cause more problems if i leave it out?

 

Other than failing inspections (if you have them) and a constant check engine light, it won't cause any problems.

 

PCM may or may not whine about cat efficiency...... some are more sensitive to it than others.

 

my 96 Dakota didn't care... but my damn 01 Durango, well, it went a whole 138 miles before it threw a fit and lit the check engine light, I had to put a new cat onto that one..... I wasn't happy about that.

 

I had mine replaced at 200k, doubt the cat was still working efficiently. So bought a high flo low restriction cat. made a noticeable difference in acceleration afterwards...

 

My 2000 durango with the 4.7 hasn't had any issues, I also don't have the second one hooked up to the exhaust, im not sure how much that affects it, It does run pretty lean.