Afr's

Good day guys, bit new to all of this not a mechanic nor tuner but i won a 2008 Wrx-S HatchBack. Upgraded Intercooler, Turbo (VF40) and fuel pump.

I had a tune on my TD04 But was running breathless higher mids and top. So to say simple i put the vf40 which is supposed to give me high mids and tops.

My current issue is the car is tuned to the td04 but not the vf and my afrs are going crazy. i have seen 8.9 sometimes when i throttle about 80 percent once i hit boost the afrs go from 14 to 10 to 17 to 11 to 12. what could be my issue? i also sometimes idle at 12 and sometimes at 15.7 when i put AC ON I GET CLOSER TO 14.8 AND 15. So i honestly dont understand. i was told vaccum leaks or exhaust but wouldnt that be constant? i was told check maf i cleaned it seems fine etc... so before i tune i really wanna sort that out.

Hello is it possible to check with another 02 sensor

Regards Ross

With such erratic readings, I'd also suggest having a good check over the wiring - it's possible you accidentally disconnected something or forgot to reconnect? A bad earth is a common fault, so if you missed retightening one?