I agree with the others about low and slow not being good for this lean a cut. I'm also confused. Is it a tenderloin or just a pork loin? 5.5 lbs seems awful big for tenderloin. When I buy tenderloin, they usually come 2 to a package and each are a couple lbs at most and only 2-3 inches in diameter at the thickest part.
Gas is an abomination!