'94 Cadillac Fleetwood has been parked at least 6 years although I try to start and run the engine for a minute every 4-6 months. This morning I threw a battery on it and it started in 10 seconds. Lowered tire pressures from storage pressure and drove it home 60 miles with no problems. Checking my file and see the last time I filled up was October 28, 2014. Cant feel anything unusual in how it drives. Maybe because it was premium gas? My Saturn Ion which had 5 year old regular had some pinging until I used up that gas and refueled. So does premium degrade less than regular over time? I'm at a quarter tank and want to burn off as much as I dare before filling it up again.