My 825i cuts out or misses when pulling hard to go up a hill. Also does it a little when traveling above 20 mph. I thought it might be old gas, so I added some fresh 93 octane gas (about 2 gallons to about 2 gallons of old) and sea foam. It doesn't seem to be any better. Any thoughts or should I just use up the gas as is and then put new in. The gas runs my generator fine.