Hi, i have 1997 Pathfinder 4x4, and it dies intermittently. It all started when i changed brakes. Car started to cut off on me. it could happen any time, stop lights, while driving, but does better on hwy speed or while idling in park, but once in gear will not last for more than 2 minutes, i have to keep my foot on gas to keep it running. I do have MIL light on, with P0420 code. I looked for vacuum leaks, but did not found one. Any ideas ????