performed one high speed taxi- - run-up was fine immediately prior. taxi'd back for departure, and did another run-up. when the mag was turned off, the plasma EI did fine. when the EI was cycled off then on, there were a couple of 'pops' in the exhaust. it has never done this before (new engine, has maybe .3 on it), and I'm suspecting it was running a bit rich & warm after the taxi test. anything to be concerned about? mag on left side, P2+ on the right side. FP, carb. 0360.