Fuel mileage and auto start

Ill start off by saying I added a winch to my truck. Disassembled the grill to do the wiring right. I also added a new yellow top 27f group battery.
I ran the truck normal, I went home and tried to use my auto start and it will not function now. I proceeded to drive around a bit, said what the hell ill get fuel. I filled up with 88 octane as usual. Left the station an noticed my fuel economy went from 430 meg's per tank to now over 600 mpg's.
At a loss about this

 

When you disconnected the battery you reset the "memory" associated with the fuel range per tank. After a tank or two I'm sure your numbers will revert to normal.

The auto start not working likely has to do with the battery being disconnected as well. Is this an aftermarket automatic start system or the OEM remote start?

 

i'll keep an eye on that through these next tanks. no this the factory auto start, it's sequence is the 3 clicks on the lock and it would beep twice then start

 

Still no fixes yet.

 

Normal. Once you visit the gas station a couple more times, your range will resume the normal range you’re used to seeing.

 

Still unable to get the factory auto start to work. Erased codes. Still not working

 

i thought on factory key its 3 clicks on the third you hold it?

 

It is

 

What codes?