Ok. On my last "tank," which included 10 gal of wvo and 20 of diesel, I was able to drive a total of just under 700 miles giving me 23.3mpg. Assuming there was more fuel in the wvo tank than I thought, this calculation would be falsely high. An other possibility I'm considering is that in removing my broken front anti-noise capsule and tying up what is left of the rear one, the reduced aerodynamics could have something to do with the drop in fuel efficiency. I've sent inquiries to junkyard databases so far with no luck. Do any of you drive around without the anti-noise capsule? It's name appears to indicate that aerodynamics is not what it's for but it doesn't look like it would hurt.