Every once in a while we hear about markedly sub-par MPG data. The dealer says the car is fine, but that is just about useless..

I think a reasonable test would be to warm up the car, and then check MPG over about 10 miles R/T going 30 - 40 miles per hour on cruise control. If the hybrid drivetrain is not optimizing the ICE, it will show up.

Any better ideas ?