I have an 01 pathfinder that seems gutless getting up to 60mph+ and up hill or just getting up to speed in a hurry. I tried all the tune ups. spark plugs, filters, checked exhaust for blockage with intake vacuum test. no ses light on. took it to the dealer they said MAF sensor. i changed it with an aftermarket one. there was no difference in the way it performed. truck runs smooth just in and out of having any balls. guessing its electronic. gas mileage very bad too. read something about others with this similar problem. any guesses on fixing my pathy?