The Ford F-150 is the best-selling model in the country, and that seems to be true no matter what the economic conditions are. Even with gas prices hovering around $4 per gallon, one thing remains true: Americans love their pickup trucks.

Still, the F-150 isn't completely immune to shifts in the market, as recently demonstrated by the May sales totals. Ford reported that "for the first time in decades," the V6 engine option on the F-150 outsold the V8, USA Today reports.

One might assume that drivers were simply trying to save money – but that's not entirely true. The most popular V6 engine was actually the turbocharged EcoBoost, which is $2,000 more expensive than the base V6. However, the EcoBoost has the highest fuel economy of any engine Ford offers on the vehicle, something that buyer's have been going for lately. The EcoBoost also has higher horsepower and torque than the base V6, which justifies the cost to many buyers.

"That's a premium engine that almost always comes with premium content," Ford VP of sales Ken Czubay told the news source.

The V8 isn't going anywhere soon – it still made up 45 percent of all sales. But at least for May, it appears that the V6 was king.

Drivers looking for a vehicle with excellent fuel economy may want to consider New Jersey State Auto Auction, which offers both new and used cars for sale.