i drive a 2oo5 chevy silverado and i had about a third of a tank of reg gas and by gun i saw a place nearby that finally offered E85!! Well i pulled in and topped off the empty 2/3 of my tank with the E85 (all the while thinking my Silverado was flex fuel) but before i left the gas station, i looked thru my truck manual, checked my VIN and found IT IS NOT flex fuel! Well, i had places to go, it was raining, so off i went. about 8 miles later my engine light came on. I havent noticed ANY poor effects in my truck but that light is on, well i took it home, made some calls, and got on teh internet, and here i am. the posts have been very helpful and i'm glad i had a third of a tank of reg. but what about that light? what are the dangers? should i syphon out some of the tank and refill Reg.? Luckily i dont drive my truck alot nor long distances nor do i need it for several days, so i'll wait for info from the pros in here. thanks for yalls time.