if the engine is lean missing at idle, it will be disconcerting but not too much of a problem, but only if its at idle. if it miss at WOT or just driving down the road it will melt the cat down. the miss is probably causeing the smell. when it misses it shoves unburnt fuel down to the cat, cuaseing it to get REALLY hot and may have melted it down so that you look like you have a cat, but you don't really. does it pass emmissions(besides idle)?? does your jeep have an exhuast leak? a leak in front of the O2 sensore will cause it to run poorly. An intake manifold will make it run lean too. take your propain bottle and hunt around for intake leaks. do you have an adjustable TPS. if it is trying to run off idle it might be getting too lean.

as for the funky smell... i'd have to smell it. funky isn't descriptive enough.

A five gas analyzer is basically a smog machine. it measures O2 CO2 CO HC and NOX. you CO level is basically your Air-Fuel mixture indicator. NOX is combustion temp. the others follow tghe CO and compustion temp around.

For starters i would make sure that the fuel pressure is at spec at idle, make sure your TPS is proporly adjusted, and do a basic tune up. if it still is lean missing at idle, check for intake and exhaust leaks, then go get some number at a cheap smog check staiton. sometimes those guys who arn't busy will do an unoffical numbers for under 20$