4th gear for maximum efficency?

[thoraldshib]

I just watched "Robot Catina's" youtube video on fuel economy testing "S4 E43. 2000 Honda Insight" where he tells about his research using the Insight and that it achieved best fuel economy without IMA working, and while top speeding in 4th gear. I have a gutless Lean Burn 1999 Honda Civic D15Z7 with long gear ratio transmission (dyno proven 86 HP to wheels) I have never exceeded 42 MPG despite expectations of 48-50 , I'm thinking of trying driving it without using 5th gear, car is so gutless I normally drive it up to 50 MPH in 1st gear then plop it into 5th gear. Has anyone else tried this? I always thought 5th gear would be the best on economy

[Gasoline Fumes]

I just watched the video too. And I also have a 2000 Insight. I average 64 MPG using 5th gear as much as I can. I suspect Jimbo might have a clogged fuel filter.

50 MPH in 1st gear probably explains why you only get 42 MPG. If that is really necessary, something might be wrong with the car.