I am from Colorado and am working in Little Rock AR. I started using B20 about 6 months ago in my 99.5 F-250 and have had no issues with it even on my trips from here back home the altitude +10,000 and cold 0-32F didnt effect the engine in any noticeable way. I have had to change my Fuel filters and noticed more crud in them but the last time they were pretty clean. It also quieted my engine some. I love it but not the price about .10 higher than #2.