[Diy_efi] Can constant WOT operation destroy a muffler?

[Andy Harvilla]

Hey guys,

I have an unusual "problem" (if you can even call it that) with my  
Jeep Wrangler that I think can be attributed to near-constant WOT  
operation.  Every year, no joke, I have to install a new muffler on  
my Jeep because the old one cracks underneath in exactly the same  
spot.  Even after only a few hundred miles of use, you can see the  
metal casing begin to warp and swell, presumably from high heat.

It occurred to me that this might be happening because of the way I  
drive the vehicle.  The little four-cylinder engine has no power  
(considering the 33-inch tires it's pushing) and I'm nearly always at  
full-throttle just to get the sucker to move... going up hills,  
highway driving, etc.  Do you think the computer is enabling WOT mode  
and richening up the mixture, which in turn heats up the catalytic  
converter and slowly melts the muffler?  There's always a constant  
rich smell and the tailpipe is usually black.  I had to install a cat  
due to inspection reasons (the previous owner hollowed it out), but  
before then, I never had an issue with mufflers blowing out.  It  
seems like the converter might be the root of the problem.  One of my  
friends owns a Wrangler, drives it the same way, and also replaces  
mufflers annually.  We always thought it was "just a Jeep thing"...  :-)

Andy