Last Thursday I bought an 07 HD with 43,xxx miles on it. Truck is really pristine and has obviously has been taken care of. The test drive with the truck and the night that I bought it the truck ran excellent and smooth. We were out of town, 4 hours away. The next morning we drove home. My wife drove the HD truck home and I drove the other vehicle. About an hour from home we stopped and put gas in vehicle and unknowingly I put about 15 gallons of 87 octane in the truck. She drove the truck on home. Later that evening Friday I get in the truck to ride around and the truck runs awful, it sputtered around when I hit the pedal and really got on the gas, but as long as I drove normally the truck done fine. I immediately think about putting 87 grade fuel in and go pick up some Lucas Oil Octane booster and drive some more, no change. Yesterday it had 1/4 tank of fuel left so I went and topped off with 93 octane and still no change with how it runs. It does spit white smoke if you get on the pedal hard and last night the check engine light would come on and go off when I would get on the pedal, once normal driving resumes the check engine light goes off. It's like it's starving for fuel, there is no pinging whatsoever like a vehicle does with low grade fuel. Been trying to research all I could and thought it might be water in the fuel so I added Heet water remover and still nothing changes. I'm starting to get a little worried about this truck so wondering if you guys can help.