hi,
last year i went for emmission and failed a few times. i couldn't figure out why. changed plugs wires etc. took it to shop and they discovered nothing was left inside my cat, theyasked me if i hollowed it out, and i said no which i didn't. we'll likely i had a warranty on my random tech convertor, and didn't pay a dime 4 the replacement. i want to know what could have caused this? should i be very worried? at the time i just had the borla exhaust and slp shorty headers and the cat. also, do u recommend routing the spark plug wires over the valve covers cause i have burned a few set over the last couple years. i'm all ears guys, thanks

 

anybody?
bueller. bueller