Ruined catalytic converter in 6 months
i picked up my 97 sr5 5 speed in august last year and my first and only code was a po420. among other things it got a new cat and more recently a new muffler. it wasn’t oem, but it was a $750 cat from a shop with good reviews. recently my truck is suuuuper sluggish. the mechanic i trust checked my plugs, maf, and did a back pressure test thru the 02 sensor hole to verify cat is bad again. exhaust shop says it’s less than 1% failure rate for their cats. my engine doesn’t seem to burn oil, it leaks, but it never produces white or blue smoke unless it’s from the cold air. where would you all start for burning oil? any experience ruining cats quickly? i’m willing to suck it up and pay more for a beefier cat i just don’t want to kill it so quickly again. here’s the beaut in question