It took some professional help to get it running fairly well the first time- - - - -are you really sure you want to second-guess their work on the off chance you might make it run a little better? Jack up one wheel at a time, and see if the brakes are dragging. I'd think long and hard before tinkering with an engine that's been fine-tuned by a professional shop in hopes that you're going to wave a magic wand and make it all better.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!