2007 g35 coupe AT:
when driving to work, the CEL came on. when i got there i used the manual method to pull the codes. i counted P0420 and P1547, then cleared to see if it would repeat. during drive home the CEL stayed off until i started decelerating. it would then begin to flicker briefly (not like when counting flashes) until i accelerated again. i didn't feel any shifting issues when the car downshifted to accelerate. it might have been a little rough a idle; may have been my paranoid mind. couldn't see any similar issue here but i'm hoping someone has an idea and this is a shade tree fix and not a major fubar.
thanks