My check engine light went on 2 days ago while driving. Truck slows down, then shakes, then drives okay. Did the same thing the next day, except after driving for awhile lost a little power once again. This happened to me in 2009, brought to dealer, I forgot what they did but they also gave me new batteries. This time I have code P2509. tried looking it up and I see in some posts, new battery but my truck is starting fine this time. So what else could it be?
Update - Brought to dealership last week, they claimed it was a corroded wire from battery cable to ECM/PCM. Well guess they were wrong. Truck rode fine for a week, then our friends borrowed it to take it to update NY this week. On the way there, Sunday, the check engine light went on, same thing, shaking, driving slow. Today he calls me to tell me the truck won't even make it up a hill. Great, 5 hours away!