If I had a 2 degree timing advance and then reset the ECU (by unplugging the battery for an hour), would the timing advance be lost?

I recently bought this car used, and it was super fast to start with--way faster than my old stock one. It's an auto with a cat-back exhaust and K&N panel filter. I can't tell if it had any more mods and can't contact the previous owner. But I think he had the timing advanced since it ran faster in all the RPM's and especially the lower end. And it seemed to idle higher and louder before. Or maybe he had a piggy-back unit and just disconnected it before selling the car (would the ECU even hold the piggy-back's A/F settings?).

Since resetting the ECU, I have experienced low-end bogging and have lost much power in the lower to mid RPM band. Also, a faulty MAF was manifested shortly after the reset, but no CEL light came on (this makes me think he maybe put a resistor on the MAF, thus advancing timing indirectly; but i didn't see one installed). The MAF was replaced by a dealer. I asked the dealer about doing a reflash at that time, and they said it wasn't necessary.

Does anyone have a clue of what the previous owner did to the car? and why this would happen after the ECU was reset? Does it need a reflash after putting in the newer MAF (my last 01AE did)? Thanks for any help!

 

That is perfectly normal for it to act a bit rough after resetting the ECU. The ECU wont hold AFC settings if it's disconnected, but it will hold the timing advance. You can verify with anything OBDII scanner/logger. Stock is 15.

 

I have the same exact story with my 5.5 gen maxima like the OP

Fast maxima as hell the first few days,then lost tooo much power despite all the work and parts poured at it.....