funny thing. The standard answer has always been "yes." But my friend who's a master mechanic, who helped me design and make a custom airbox mod (pictures to follow) told me the ECU will retrain itself without a power-off reset. He's a Jeep service manager, so it may be different for Jeeps. But now, knowing his credentials, I can't say with authority whether you need to reset it or not.

Anyway, it's no big deal to reset it. disconnect the positive battery lead when you start the project. by the time you're done, the ECU memory should have bled. reconnect the battery, let it idle for 10 minutes, then go for a nice, spirited 15-20 minute drive. Voilla!

 

I think you're supposed to disconnect the negative

 

umm, the red one, man