I do not think that I noticed a drop in fuel economy. However, it may be because my CPV was faulty from the factory? I remember the loud ticking noise from the engine bay right off the dealer lot when I picked it up. I would notice the hard start after refueling once in a while, and just shrugged it off without any further thought.
When I took it in to be replaced at around 15,400 miles, I did not notice a difference in the ticking (still present after being replaced). Have not dealt with a hard start after refueling as of yet, but I do have a new knocking sound coming from the engine bay. Dealer calls it normal. Says it's the injectors. I've had this truck for almost a year and a half now with nearly 16.5k miles and never heard this noise before them replacing the CPV. I decided to replace myself today. I will let you know if my MPG's get better or not