You can't loose the flash itself, but you can loose the Revo settings. However, that would require the battery to be disconnected. What makes you think the car reverted to stock and doesn't have an issue like a bad DV, clogged fuel filter etc. that is robbing it of power?
I turned my car off and got gas turned back on normal stage one power then again 2 hours into drive I feel it the power kick down and normal stock boost pressure and normal stock power output it's an obvious thing