also, to keep in mind the CFC program only gave you the tax credit toward the lease on a new car (and some used cars).
so it's not like you junked your 91 Dakota and got 2K to go buy an A body.
the program was a double incentive-- removing some cars that characteristically were known to possibly be polluters as well as removing cars that got poor gas mileage AND encouraging spending by basically giving participants a "down payment" on the lease of a new car that got better mileage and ran cleaner.