Hey everyone I am new to the scooby family just bought an 02 WRX and loving it but I am having an issue with it, a few days ago I popped a p0171 code and after hearing the spudder I changed out the A/F ratio sensor which solved the problem and the engine code went away but heres the thing I was also having issues with a hesitation once I got up to about 4500rpm 1/2 throttle and on top of that I am not getting full boost when I do go WOT it still hesitates and still only at 7psi. I thought it could have something to do with the tune from a cobb accessport version 1 its a stage 2 tune that the guy i bought it off of put on it. I accidentally forgot to reconnect the MAS to the ecu once i put it back in and it ran smoother without the hesitation. This has me baffled as far as the hesitation is concerned , why is it running smoother without the MAS then it is with. Any help wouod be great thanks.