Well, Im not entirely sure how this would work on the Duratec. But I had a problem once, a couple of years back, I downshifted going up hill, and as soon as the engine was given a little more stress. I got a flashing CEL, and the engine just started shaking... Not smooth running at all. I thought I had super jumped timing... But remembering what I had learned on this website, flashing CEL ment Misfire or No fire. Took it to auto zone, they told me cylender #2 was not firing. So, I bought a new coil pack, new spark plugs... and a very nice guy on here (R_G where did he go?) sent me some Ford Racing Wires for free. Did my "tune up" went for a drive, and it ran perfectly. If you're CEL came on, I would say theres a chance of a couple of occurances. I would say you might have a super misfire, or no fire on one of the cylenders. OR it might be the knock sensor on you're engine, and basically telling you that you have rod knock, im not saying that to scare you, just telling you the possibilty. The best way to know, is to go to a local autozone, or advance auto, and have them scan the code. You get the code and post it here. We can REALLY help you from there.
