Not sure if I'm just feeding the trolls here, but here's some rebuttal:
Ignoring ad hominum attacks and thermal energy tangent, it appears your arguments are (1) work on everything blind to its contribution to the whole and (2) work on vehicle engines because they have a shorter product lifespan when compared to coal plants.
(1) Focus on every single piece and you end up with no focus at all. The question is, where would you have the greatest IMPACT. The solar panel company I work for is now building solar cells that are just a penny or two above the $0.10 per kilo-watt-hour of grid parity. Give us a few years and I think we'll be cheaper than coal. Kill coal and start building solar and wind farms! Coal and petroleum are currently equivalent in their CO2 emissions Source and we can get that power through alternative methods for less than the cost of replacing all of our cars with only slightly better mileage, which would have the greater impact?
(2) Using $250m cars on the road with an estimated average $30k/vehicle retail cost ( Source ), here are approximately $7.5 trillion (that's with a T) worth of cars on the road today. There are approximately 600 ( Source ) coal plants in the US. To improve the mileage of cars, you essentially have to replace them entirely. Cost: $7.5 trillion. Spending that money on coal plants instead would provide $12.5 BILLION on EACH of the 600 coal plants. Considering that a coal plant costs less than $1b ( Source ) to build, I am sure we can find significantly better uses for that extra $11.5b per plant.
Some additional arguments
(1) Where do you suppose the power charging your Chevy Volt is coming from? Chase people from gas and you end up with a coal-powered car.
(2) The largest 15 ocean-going ocean tankers emit as much of some types of air pollution as every single car on earth. (!!!!) Source. I can't seem to find how much CO2 they emit... How many tankers do you think we have circling the globe?
In conclusion, I stand by my position: For CO2 emissions reduction purposes only, our dollars would be better spent on improved power generation... and to beat the CO2 drum is rhetoric designed to whip up the uninformed... or to advance someone's agenda...