I change the fuel filter @ 50 K and examination of the old filter shows that it could have gone longer. I drain a little fuel from the filter every 10K and see if there is any water. So far none. Buy fuel only from places doing a lot of business. Your chance of water in the fuel will be much less. I do not belive there was restriction of fuel, I believe it was water. I don't know everything but between 1966 and 1982 I was driving 18 wheelers every day. I owned my own for 10 years. I had problems with water in fuel and I solved it by putting a drain valve on the bottom of my tanks and draining the water every morning before start up. I was always surprised at how much water I would get. Cold night air outside of the tanks and warm air inside the tanks would cause condensation (sweat) that would roll down the sides of the tanks and settle on the bottom. When it gets deep enough to get sucked into the fuel filter and you get a couple of inches in the fuel filter your engine dies. Alcohol based additives that displace water work but I have seen it over done and good bye engine. In my opinion it is best to drain out the water, if any. Sometimes there won't be any water when the outside and inside temperature isn't much different. We had metal tanks, aluminum or steel. Our Rams are plastic and I think that could reduce the condensation. We had 100 gallon tanks and our Rams are 35 so that may contribute to why I have not seen any water. REGARDS.