OK, so it's been a while since I've been on the site and I'm finally finding the time to get back into both maintenance and low scale modifications to the Tahoe but have been chasing some codes that have gotten me to the point where I'm looking for some advise. So here's the backstory...for the last two months or so I've noticed a decrease in mpg but without any codes chalked it up to the engine having over 125k on it. However for the last 3 weeks or so I've had some rotating engine codes that I've been chasing, with my limited means. So with nothing more than a code reader, mpg trends, and the all mighty butt dyno I've been chasing three codes: P0132, P0134, and a P1133 (of the three the P0134 is the most consistent) and a P0161 (which I figured out). So far I have done, or noticed: Noticed Decreased mpg Occasional feeling of a "stutter" while at idle Engine temp operating slightly higher than normal (210 range...but never higher) No hesitation on acceleration Done Replaced O2 sensors 1/1 and 2/1 (noticed wire rubbing of 1/1 on the drive train) Did a poor man's check for a vacuum leak using throttle body cleaner and along intake Reset and resealed air intake At this point I'm kind of at a loss for where to go next, so any suggestions would be appreciated. Thanks again.