More data needed for diagnosis, but here's start point - azcentral.com
My granddaughter has a 2010 Nissan Sentra that slows down quite a bit when she drives to Phoenix from San Diego. It slows down without warning and will not speed back up when trying to accelerate. The Internet talks about the car heats up and the transmission fluid gets so hot that the computer drops the speed to save the transmission. When contacting Nissan, they tell her to bring the car in for a check up which will cost $100 just to hook up the computer to check it out. Answer: Gary, you left out a lot of data and trying to gather symptoms via a third person is a huge financial risk for you and me. How many miles does it have on it. Has the fuel filter ever been changed. If the transmission was burning up the fluid, any good tech can pull the dipstick and smell burnt fluid. If the fluid is red, clean and smells good then it isn't the transmission that is causing this issue. All we get is serial stream data and one has to be really good to read that data. One has to know if he gets 0. 90v from the O2, is that good or bad. The most important things you cited was this only happens on the freeway, so a substandard fuel supply or an overheat would be a good direction to go. Mark Salem is an ASE master technician. Source: www.azcentral.com
