Nope.....it's ROM. Now all of the learned stuff like corrections and random bits that the ECU uses to anticipate your driving habits are lost. All of the ROM data is saved in Non Volatile Storage

OK cool thanks
I gotta do seats and steering wheel so i have to disconnect the battery

Hi Hansoac,

I'm the new guy, but maybe I can help a little - from my tuning experience those AFRs are pretty good. 13 being a little on the richer side, but better for making power and keeping EGTs down. 15 is a little more lean, but better for fuel economy and causing slightly higher EGTs (it's normally used for cruise control maps, I believe). 14.7 is stoich, which is the best for normal and safe putting around...

The problem may come from where you're reading the AFRs. I'm still learning the 370s, so please take this with a grain of salt: the normal post-cat O2 sensor could be giving the code due to your lack of cats. That O2 sensor may be programmed to read cat efficiency (it is in my STi) and if they're gone, well... they arent being very efficient, thus throwing the code.

I hope some or all of this is useful. Good luck!