As part of the federal goverment's EPA imposed clean air act. All of the gas sold in NJ during the winter months contains 15% MTBE. So in effect we are forced to run Gasohol in our cars, and yes economy does suffer.
On a more serious note, there have been a lot of reports of this additive making people sick, and consideration has been given to removing the additive, but so far to no avail.

Another pain is the new inspection system that requires the treadmill test for emissions where the car is actually placed on a dyno and an emissions reading is taken of a simulated ride in the car. Management of the transition has been horrible, and significant lines have become the norm. I went last saturday in a huge rainstorm, and much to my surprise there was no line, so I was in and out in 10 mins. Talk about luck -

Best wishes and take care,
George Androulakis