I cut the cats off my car a couple of years ago and been having spiratic problems with my car. It dies at idle alot, while on the highway when I try to punch it, its a cutting out feeling but the car completely falls on it's face and rpm's shoot to 0 until I let off the gas. I've noticed tht as soon as the rpm's reach 3500rpm it starts doing it and won't let me get over 3500rpm..also backfires when it falls.. Is this caused from not having the cats? Please email ur answer shawnwray78@yahoo.com