My 2012 with essentially the same motor has the same issue in the summer in Texas. When I run 87 octane, taking off from stop lights under medium loads will have slight pinging for the first few hundred RPMs. The only way I've gotten it to stop is running E85. Running premium should also have the same effect.
Running premium or E85 allows the ECM to pull less timing do to premature detonation(Pinging). The only reason I can see your shifts being improved is the ECM is pulling less timing, and torque management is having to intervein less. One trick you could try is to cool the intake air by bypassing the coolant lines that go through the throttle body. If your in a warm climate, your just dumping heat into your throttle body, raising the incoming air temp. The whole reason coolant is run through the throttle body is to warm up the combustion gases faster for better emissions.
Running premium or E85 allows the ECM to pull less timing do to premature detonation(Pinging). The only reason I can see your shifts being improved is the ECM is pulling less timing, and torque management is having to intervein less. One trick you could try is to cool the intake air by bypassing the coolant lines that go through the throttle body. If your in a warm climate, your just dumping heat into your throttle body, raising the incoming air temp. The whole reason coolant is run through the throttle body is to warm up the combustion gases faster for better emissions.
