Sudden Gas Mileage Drop / Poor Fuel Consumption, HELP!

[Gascan]

Gascan did you get this resolved? What was the cause?

Honestly I’m not sure… I’ve got a few observations:

I’ve switched to using strictly ethanol free fuel and my MPG consistently went up from 8.5 MPG to 9.5 MPG with strictly city driving.
Highway mileage is similar to what it was before this “drop” It’s currently 12.5 to 13 MPG when the truck is loaded down with gear and a roof top tent on top; rolling at approx. 70 mph. Looking back at historical data (2016), I averaged approx. 11.8 highway MPG with the truck loaded down and two heavy kayaks on top. Not a direct apples to apples comparison so I’m unsure if my MPG’s improved or stayed unchanged.

Thinking about this thread recently, I looked at my Land Cruiser’s maintenance notes and realized that maybe a month or so before noticing my sudden drop in MPG’s, I had installed a new A/C compressor. Long story short. My old A/C compressor seized mid-drive and I cut the belt in order to keep driving. Due to a large supply of procrastination, I drove around Florida without A/C for about a year. At this time, I’m leaning towards believing my 10.5 city MPG was due to the engine not having the A/C compressor bogging it down. And 9.5 city MPG now, with A/C, would make sense.

I do intend to pull the cat in order to see its shape in the near future as per the suggestion of some members here. Any proven ways to keep the 02 sensors from tripping the CEL without the cat on an OBD2 Cruiser?

 

[cruisersurf]

Interesting. Thanks for the folllow up.

 

[Gascan]

UPDATE: It appears that a partially stuck rear caliper - the inner pad would not release, cause continuous friction on the rotor - was also contributing to my poor fuel mileage for the past year. Since fixing it, my mileage went up by approx. 1 mpg. I’m currently getting about 10 mpg on “up to 10% ethanol” winter fuel blend strictly city driving, with my work commute being only 10 minutes long... Under these conditions, I see 10 mpg as a win!