My battery connector kept coming off one day when I was driving and every time i reconnected it after parking my car would idle at like 100rpm (didnt even know this was possible). It would eventually idle normally after I drive around for a while. What exactly happened here, and is it something i should worry about? (connector problem has been fixed btw)

 

Every time your battery is disconnected the computer must relearn its idle air .... running air...... fuel to air....blah blah... lol, all over again.

 

Also im pulliing cel code 31. I looked it up and it says: 7mg(t)e air flow meter signal. Does this mean my mass airflow sensor is bad or the system has a leak, or am i just pulling random codes for an engine i dont have?

 

Wow! I reset the ecu, and then "trained the car" into performance driving. The difference is amazing. The code 31 ( which most likely from driving very slowly after battery resets and having a BFI), went away from teaching the ecu that there is much more airflow than stock. The car runs so much smoother. It is a lot more responsive, and honestly it feels like I have 7-8 more hp and a wider power band.

 

Yeahh it can do that