So I have an 01 XJ and have been having the issue of a "sputtering" sound coming from the muffler when I accelerate while I put my foot on the gas.

Accelerating between 0-20mph the muffler sputters and I hear knocking/banging. It eventually evens out and goes away BUT gets worse no matter no matter how fast I am going when I drive over this big suspension bridge near my house and or steep street goin up a hill. When I am going over the bridge or steep incline street it loses power as I try to accelerate and start to struggle and slows down all while sputtering. So what I am trying to explain is that:

*0-20 MPH the muffler makes the sputtering sound and I hear knocking while accelerating

*20+MPH Sputtering goes away entirely but still don't feel normal back pressure.

*When going over the suspension bridge near my house or a steep inclined street when goin up a hill (doesn't matter how fast or slow I am going) the jeep really struggles and sputters while I am trying to accelerate as I try to get over the bridge and ends up slowing down significantly as it struggles to go over because it can't jeep up...and the knocking is still there.

Anyone know what is going on? It also idles rough...

 

Sounds like your catalytic converter or muffler has failed internally and is making the noises/backpressure.

 

Def this and or possibly due to a rusted out exhaust or check welds from the front pipe to the cat for leaks..Did you run diagnostics?

 

As above, run an OBD2 check,

a stuffed Cat will throw P0138, but weirdly not a CEL (in my case anyway)