Loss of power after being rear ended

This morning I was hit from the rear while slowing for a light. I was not a hard hit really. The other driver sped off with a print of my hitch in their honda. I got out and there was no visible damage but once I got going things were not right.
I can hear an exhaust type hissing sound and at the same time the exhaust sounds more subdued. It has some kind of aftermarket muffler that normally has a bit of a throaty grumble and that seems to be gone at low rpm. At high RPM the thing sounds like it is screaming.
Hills that I could go up in 5th while losing a bit of speed or in 4th while picking up speed now I am slowing to 50-55 by the top screaming in 4th. I have checked the tail pipe and I can’t detect any leaks or anything.
It is a 98 manual.
I have no codes.
What on earth could have happened?
any ideas would be appreciated...

Sounds like the tail pipe got pinched off.

Yah, sounds like that.

The OEM Tail Pipe hangs way out there.

Smacking it on the rear results in one of two outcomes:
It bending down.
It folding up towards the axle.

Most of us who Off-Road our Jeeps cut the tailpipe flush with the rear spring hanger to keep it from folding up and wrapping around the rear axle.

Ya that is really what it feels like but:
1) I had a big hitch still in from moving a trailer around this weekend so I don’t think she came anywhere near the bumper.
2) My tailpipe is trimmed up nice and tight like WB9YZU suggests to keep it out of the rocks and such.
3) I have been under there on the creeper three times now to check the pipe from the header to the tip and it is all fine at least on the outside.

So what acts like a pinched pipe but dose not look like one?

Blocked cat. Gently bang on it to see if the accident damaged it. If it rattles or makes noise, the internal substrate has broken loose and could be causing a blockage.

As suggested, the crash either busted the matrix inside the cat resulting in a blockage, broke the exhaust causing the leak noise, or it damaged an O2 sensor.

I'd bet on crimped exhaust somewhere you didn't see... did it maybe collapse right where it goes up toward the manifold? Maybe the inlet or outlet of the muffler got pushed in a bit and is blocked off inside? If it's an OEM style muffler they sometimes have a weird flare-crimp sort of setup holding the inlet and outlet tubes into the end panels instead of a real weld, and it can either pull out or push into the muffler body if hit hard enough.

98NWCherokee said:

Blocked cat. Gently bang on it to see if the accident damaged it. If it rattles or makes noise, the internal substrate has broken loose and could be causing a blockage.

Click to expand...

98NWCherokee for the win. Tim for second. I don't know if the hit caused it. Hard to say but the CAT code came on yesterday. The loss of power has subsided quite a bit... stuff must have moved around some more in there. New cat on order.
Thanks for the help