Crazy Fuel Trims

[swathdiver]

The cats were going bad on my truck so I replaced the Y-Pipe with new cats from Magnaflow.  The alcohol content (to 3%) and fuel trims were reset about 200-300 miles before this data log which was done on 93 octane gasoline.  While the cats were acting up, the LTFTs were usually about -1% to -2% on Bank 1 and -2% to -3% on Bank 2.  The engine runs great, makes 302 Rear Wheel Horsepower at the drag strip, has zero misfires but has always gotten poor gas mileage.

 

Can you see anything from this data log?  I've tried to make this run short, it's about 90 seconds.  Includes idle in park, in gear, pulling into a turn lane, waiting for traffic to pass and then accelerating on the ramp and up to speed on the highway.

 

Thank you.