I've had this 2004 wrx for a few years now. Here's the story. I bought it salvaged, its rebuilt, from the accident the timing belt flew off so i had to replace the valves and all that. Since I've gotten it running i've had CEL codes non-stop pretty much. First there was a problem with my rear o2 sensor. Fixed that CEL went away. My engine had absolutely no power and another CEL came on, now it was the knock sensor, fixed that, car ran perfectly, i thought. Then after that I got another CEL and its a misfire in cyl 2. I tried swapping the coils with cyl 2 and 4 but then it seemed as if both 2 and 4 didnt work, i could barely get the car to move from first gear so i was scared of taking it to the shop. I switched the coils back but now it still seems like both cylinders aren't working. Any ideas?