I have a 2011 STI Hatch with an Accessport, SF Intake, and Turbo Exhaust. It sat for about a month and a half while I was away and when I came back to drive it down the east coast, the battery was dead so I got a jump to start it and head south from Rhode Island. I was noticing some pretty awful performance and gas mileage over the 15 hour trip. I averaged about 16 mpg and was not getting the performance I had gotten before. I thought it might be from the fuel sitting so long, but I filled up the tank several times over the trip. My intake filter is in rough shape, so I plan on replacing it, but I wasn't sure if that was the problem. Should I uninstall and reinstall the Accessport since the battery died? Not sure where to go from here. I'm fairly new to the mods. Any help would be appreciated!

sounds like you jumped in and took off down the highway immediately after a computer reset - the car may need 2-3-4 "drive cycles" to re-learn the sensors and complete the monitors.

 

coupled with possibly phase-separated ethanol-laced fuel - 'could' equal poor performance.

 

you might scan for pending codes , you may also need live data to see what's up.

 

no signs of rodent damage to any wiring?

and no offense to the local experts, but there's even more STi-specific info on NASIOC.

GL,

TD