I work at a auto parts store and I seen something wierd the other day.
A man came in asking were he could buy natural gas for his truck. I have heard of propane powered trucks so i figured this was what it was. So i went out to the parking lot to see this truck, and as soon as i walked out the door i seen that the truck was a flexfuel vehicle. So I questioned the mans sight, and ability to read his owners manual, but low and behold i walked around to the drivers side and there were two fuel doors next to each other. The man opened the door and there was a fitting ""like a 3/8 air line quick connect" as if there was a hose that plugged in there. Than i looked in the bed and there was a large tank for the fuel, It was plastic like a water tank. I looked in the fuel door and there was a sticker that had some specifications on it,And a ford part number. i looked in the cab and there was two fuel gauges. like i said ive heard of propane but not natural gas "which was clearly stated on the safety sticker inside the truck".
"that the truck needed to be operated at least every two months on gas to ensure longevity". There was also a large diamond on the tailgate with "cng" in it. I searched and they do conversions but what baffeled me was the ford part numbers. What did i see?
The Army has factory installed CNG Flex Fuel vehicles. I have driven many of them and they are ok, but limited on real power. I think I have seen some in the Washington State DOT lots as well (can't be sure about that though).
So, yes they come from the factory like that, but for "special order" only.