My 2010 cobalt sstc is having problems. i switched from the trifecta 91 tune to the trifecta E47 tune. my car is kinda sluggish, it wont let me build any boost after i drive down the highway for about 5 minutes, but boosts fine in town. i was throwing a MAf performance code so i replaced the maf and still having issues. i now through a cyllinder miss fire in 1 & 3. the RPMs will hold or decrese very slowly after i let off throttle. Is this all tune related??