A/F noob issue part 2
 

I have an GTM Stage 1 supercharger on my '10 370, have had it tuned in May '15 and now am having a glitch with my A/F where as I am going through the gears in normal speed the a/f hits 16~17 at about 3500 rpm.
I have pulled the battery cable to reset the ECU and also reflashed my tune,
and have had my tuner tweak the timing/ a/f ratios twice.
The only real change that I have made b4 I started having this issue is changing to a softer spring in my Syanapse diverter valve.
BTW the this is my second BOV as the first one ( turbosmart) and the current one flutter like hell in when driving normally. The softer spring lessens the flutter .
I don't have any issues when pushing the car at higher rpm & speed.
So these issues occur when I'm mainly daily driving.