... And then I started with grille blocks...
This was phase one, done yesterday... Full, 100% grille blockage... A good thought,but about eight miles into my drive to work, the engine got too hot(225F) and I removed my upper grille block, leaving the lower in place for the remainder of the drive... Now, the engine was partially warm when I first set off, but despite having to stop(engine idling during this) and remove the upper grille block, that trip returned a shocking 39.3mpg indicated... The best I got before with similar conditions, was about 37 indicated, with lower speeds...
When both grille blocks were on, there was a noticeable reduction in throttle(load) required to maintain 55mph... Usually, it takes between 36.1 and 36.5% on flat ground, but I found the car wanting to accelerate past 55 with as little as 35.7%... Intake temps were probably about 20* above ambient during this, which also helps with mileage...
I'm currently revising my upper grille block in hopes of not having to remove it tonight