Hi I have an Audi A6 2.0 tdi 2006, just recently it has developed a misfire. I took it to a diesel specialist who said i had fault codes on the injector loom, which is located under the rocker cover. I changed the loom and cleared the codes, but misfire was still present with no codes showing. The misfire got steadily worse it was on tick over and at 1600rpm, it disappeared over 1800 rpm, and comes back at 3200rpm I have done all the basics eg. fuel filter / air filter but no difference and like i said no codes showing up. When i read the codes i used a snap on solas machine which also read the injectors pressure, it pointed out that three injectors were minus and one was reading +128 this was number 2 injector, I changed no.2 injector but car was running rough on tick over so i was advised to change the other 3 which i have now done, The car ticks over ok now but there is still a misfire at 1600 and 3200 rpm . Does anybody have any idea what the problem could be????????