How bad does a clogged cat hurt fuel economy??
 

I don't know what it is... Since my last fill-up, I've only gotten 208 miles (50% highway) and the fuel needle is a little below the 1/4 mark!! I'm only getting like 12 mpg! What gives?? I've been driving it really good. So I'm going to do all the basic stuff: timing, fuel filter, etc. Also, I've really been wanting to get a 4" straight pipe exhaust soon. Not only for the sound :D, but also because I think it will help with the mpg. If my stock cat were clogged, would it really hurt my fuel economy this much?

Clogged cat will cause poor mpgs, lower power and high egts.
Most are clogged by 80k and become restrictive.
Get rid of it.

That's what I like to hear!

Loose the cat, but my guess is it is something else.

First mod I did to my truck was to pull the junk factory exhaust and put 4" from the turbo to exit. If noting else cut it out and replace with a piece of pipe.

Remember, removing or tampering with Federally required smog emissions is both a State and Federal violation and can end up costing you in penalties and fee's. [nonono]
DTR cannot support such activity and recommend that you simply replace the cat with a new.

Rich.

Oh! I thought we were talking about kitty cats! My bad. [laugh]

I had a cat that clogged on a ranger once. It caused the engine to slow down and finally over heat. I didn't know what was wrong so had it towed. I shop said that the cat had collapsed and they fixed it. I never thought that it would effect the engine that much, but they do.

Ya. Shot the cat and run a straight pipe. PETA and DOT won't approve of either, but who really cares!

(my name is Jory and I approve this message)