Towing feels sluggish - korando

cjonline

Hi, I have a 4wd 2.0ltr korando 64 plate. I purchased the car over a month ago and on my first tow I was pleased with the performance.. however, since then it's been the opposite experience, feels sluggish, struggling to get into 6th gear on motowar, mpg
dropping to 20 - 25mpg. I've had the caravan looked at by the dealer and the car.. no problems found.. the car dealer recommended getting the tow electrics checked incase it is shorting and causing the caravan to break from time to time but I feel it's the
car to be honest.  any thoughts?

Craig.