My '96 4.0 V8 manual petrol recently blew up it's middle box in the exhaust system, this was replaced by a local garage and ever since power has been down drastically and I can barely get up a decent hill. Any ideas? I'd rather go back to the garage with an informed opinion as they are not Range Rover specialists and might need to be steered in the right direction.
They are no engine warnings or error codes.

 

good chance they just used a universal muffler, to much back pressure possibly?

 

Why do you think the muffler blew up in the first place? Any issues, or rattling sounds coming from the catalytic convertors? I'm just spitballing but could the muffler have detonated because it was blocked up with bits from a broken up cat? Could one or more of the cats still be broken up impeding the exhaust?

 

No rattling before or after, however it was a pretty big bang when it went and split the middle box completely - which did make me wonder what had caused it in the first place. My garage wasn't really too helpful and just replaced the broken section - I am just a bit worried about taking it to a RR dealer and getting stung for a whole new exhaust system.... definitely feel like it's a blockage though

 

a very good point on Paul's part never even gave that a thought

 

Do your self a favor and tap on the outside of the two cats and see if there is any difference in the sound you hear. If one sounds dull while the other rings a bit, you may have a hollowed out cat and it's bits may be the source of the problem. On the otherhand, the muffler's interior may have simply disintegrated from age, especially if it's the original muffler, now going on 20 years old. It is possible that the rear resonator may have picked up some of the bits from the exploding muffler and are now restricting the flow.

 

Thanks Paul - that was part of my thinking in that an exploding box could push debris further down and clog up the rear of the system - gives me more to work on at least