I was wondering if anyone knows the diffrence in the 5.4 that are in the 350s and the ones in the 150s. y 350s gas milage sucks,the power does to,and slow as a snail. he 150s are not that way a buddy of mine just bought one and is getting like 17-18 mpg towing 2 small ztrs. And not really a dog like mine. I know it can't be the weigh because his gets be mpg with mowers than mine does empty.Any ideas?