i think you are referring to resetting your ecu and the way to do it is to disconnect the negative battery cable then hit the brakes 4-5 times and voila you have reset your ecu..I guess if you were in limp mode this would put you into normal mode giving you your power back but I dont think you would gain much just by reseting your ecu unless you have recently modded your car
It sounds like what you are after is an ECU reset. What I've been doing is disconnecting the battery and then pressing the brake pedal for several seconds. After that you may want to drive your car and set the advance multiplier for sporty driving. Do a search here or on nasioc for techniques on how to do this.
If resetting the ecu results in more power for the short term it may be a bad thing. All your are doing is wiping out what the ecu has learned. If something is wrong with your car it will have to adjust again. During the process of learning it will encounter all those bad events again. Otherwise, if you just added a small mod that the ecu can learn around its a good idea to have it learn from scratch. I would suggest getting a cable and use the free software available to log whats happening.