just installed magnaflow catback, in the instructions it said to disconnect battery so the computer can reset itself. i forgot to do this and left it on. does this matter at all? thanks

 

It doesn't matter at all.

 

On occasion, you may need to "reset" the computer. You disconnect the battery for 15 minutes or so, then let it idle for 5 minutes with no accessories running. My parent's had a maxima that was running rough and this trick cleared it up. I'm going to do the reset trick on my car since I just got the catback/flowpac installed just in case. Supposedly the car will "learn" how to run after a few miles, so this trick just makes it happen faster.

 

It's easier to do it right.
turn the key on but don't start the motor
In the under hood fuse panel pull the PCM bat & PCM ign fuses
Wait about 5 minutes
turn key off and re-insert fuses
done

 

8 year old cool trick. Been at this a while.