I have a 2003 Audi A4 1.8 with 100000 miles and it will not start, It started a month ago and started running rough with no power. I replaced the spark plugs and all was fine ran great. About a week later it was running rough again and this time I found one of the coils on the spark plug was bad, replaced it and again ran great. Now a few days ago I parked and when I tried to start again it would not. I ran the codes and it came up with the Engine speed sensor was defective, replaced the harness and it ran for about a half a day and quit again. I checked the spark to the spark plugs and that was good. I then sprayed fuel in the intake and it would start and run as long as I sprayed fuel, okay so I now have a fuel problem, changed the fuel pump relay, the fuel pump and the fuel filter still will not start, I removed one of the spark plugs and watched the spark on the plug, it sparks but seems weak (not nice and blue but yellow) I'm at a loss on what to do next can someone please help.