So I'm getting the cataletic efficiency code. The truck has 93,000 miles on it, started at somewheres around 91K. I was told that is low for the cats to go bad, so I'm wondering if the reason I'm gettin bad gas milage and why the cats died is because my Grenetalli mass airflow sensor (descreaned and bored out) is causing the engine to run rich and dump fuel on the cats. I have meant to pull it out and swap back in the stock one, but havnt got around to it yet. What you guys think?

 

My cats went out at about 60,000 miles so i think 90,000 in your case is pretty good.

 

there waurnted to 80k thru the dealership, anyone else having problems?

 

Yup! I'm getting ready to hit 80K too. I had the same MAF Sensor and ended up giving it away. Man, that thing screwed my **** up. Truck ran like shiat for a while. This is when I noticed the cats. The damn oil from the K & N is a big contributor as well. IMO I guess I'm gonna cut them out as soon as I find a shop that will help me out. Good luck man!