Ok so in my Sig I said it pulls a 12000 lb boat like its not there. Well it used to, so the last few times I had to tow the boat the truck will run fine around 70-75 mph and then it slowly backs it self down to around 55-60 mph foot is flat on the floor will not kick down or go any faster, if I wait for 5 to 10 mins it all of a sudden starts to speed up and I have to lift my foot way off the pedal and it will go back to running 70-75 with no problem no codes no check engine light ?????? I need to tow the boat again but want to make sure Im not damaging anything. HELP