I have a 2004 F350 with 85,000 miles on it and on 9/16/06 I had the oil changed at my dealer, went home with it to get other truck for oil change that day as well, the wife drove it for a little bit that day other than that it sat in my garage, oh I also filled up my tank that day. So today I backed it out and washed it and did a good cleaning to it, later today I went over to a Friends house that is about five miles away and so as I left my house I notice that my truck hand no power it was a dog and I shook it off as that it was still cold, so going down the hwy and after it was warmed up it sill had no power and it took a little bit to get to 60 mph and it would not down shift and so I put that foot pedal to the floor and all she could do was 80 mph. I left it idle at my Friends house and on the way back it still did the same thing, also I herd that flutter thing that I read in other posts as well, but just before I pulled into my driveway the engine light came on and stays on. Just so you know when I was washing my truck I sprayed water in my engine compartment as well to wash down the dirt or dust off. I am going to bring it into my dealer and let them figure it out but maybe some of you could let me know what to expect or what the problem may be, I did read through the owners manual to check the gas cap or put fresh fuel in and I never ran out of fuel and have a full tank of fresh fuel, maybe emissions problem? I don't know!!!