I just bought a 02 Ram 2500. It wont accelerate over 20mph. It starts right up,idles perfect. It runs up to about 20mph and wont go faster. It doesn't run rough or anything. It still runs very smooth but wont accelerate. The only codes I'm getting are P PCU, P1693 which is a companion code meaning there is a code in the other computer. I'm praying its not a pump!