Better mpg with tonneau cover

I remember the same article... it was in my book inconclusive still. Which is to say, very borderline how much if any improvement or degradation tonneaus, tail gates up/down/off or anything else might or might not do. At the end of the episode they seemed pretty exasperated too, especially since they seemed ready to pronounce a solid 'busted' and the cargo net showed an inexplicable improvement in mpg.

It's even possible that their results could only be valid for the model pickup they were using.. a Dakota... since aerodynamics are a top factor in relative mpg in the first place.

OP's results are very marginal... so much so I'd doubt how rigorous he could possibly have been about ruling out other contributing factors like weather, gas quality, his mood while driving and effects other drivers' habits might have had. But even so, while the results aren't fantastical it's probably a good thing to know that it doesn't degrade mpg and it actually may contribute to better economy along with other things you could do.