Ok so today I was looking at my Jeep. I have a 00 with the 4L. Anyhow, I noticed that I have two cats built in to the exhaust manifold. The guy who I bought my Jeep from put a exhaust on it right before I bought it (old one was rotted out) and he installed a magnaflow cat under the Jeep that goes into a Flowmaster Muffler. Anyhow, my questions are:

1. Is the magnaflow cat needed? There is no sensor before or after it. The only sensors are up on the exhaust manifold cats.

2. If I were to remove the magnaflow cat how would that effect my fuel MPG?

Thanks

 

i sense some silent yelling coming your way!

 

take it out, should improve performace a some but prob want notice. and it will sound meaner.

 

it is against the rules of the forum to discuss illegal activities including the removal of catalytic converters. You have an aftermarket one on there now, leave it be, you wont get any better sound /mpg without it.