check enigne light

I bought my 2001 V6 in July. Friday 10-4 she started "bucking" when I backed off the throttle in 4th (5 speed manual). It felt like the brakes were being jabbed hard, I wondered if it might be traction control though it was off. Ran poorly the next day, almost died before leaving work, seemed to...

Today as I drove home, I turned on the AC and almost instantly the Check Engine light came on. I got out my SCT SF3 tuner and read the codes. Here are the 2 codes it gave me: P0430 - Catalyst System Efficiency Below Threshold (b2) P1260 - Theft Detected, Vehicle Immobilized I am not very...