My battery finally died in my 04'. I let it sit for a week while I drove my Integra to work and it was dead when I tried to fire it up. It's not the alternator because the new battery is holding a charge no problem.

After I installed the new battery, however, my idle drops really low (around 3-400 rpm) right after I start it up and when I come to a stop, then it slides back up to around 800 and smoothes out. I have a plenum spacer, which the previous owner might have gotten a tune with. I've heard that if your battery is out for more than 15 minutes, the ECU resets. Could this have anything to do with it?

It's my best guess since I didn't mess with anything, other than swapping out a battery which I've done numerous times in my life. I'm not sure how I could **** that up. Any idea what could be causing it?

Thanks

*On a side note, why in the hell did Nissan make it so complicated to swap batteries? I had to remove panels and ****, what a hassle lol. Oh and rivets? Really? I guess I'm just used to my 90's and below cars.

 

You won't lose you tune, if the battery is disconnected for more than 15 minutes. All learned corrections, however, will be lost.

I had a similar issue when I had to do some work on the car a few weeks ago. Give it a week for the ECU to relearn and everything should be fine.