I would think that going yo a 16 front would make it worse as it has to rev even higher to get into the power. my 14 doesn't make good power until 3500-4000. try going down a tooth to a 14, then you will pull harder down low . other things that will cause issues are dirty injector, running lean/rich. so try cleaning the injector, then look at a fuel controler, pcv or vortex. does it have a stock muffler?