I have a 2006 Audi A3 S Line TDI. Chassis No. is WAUZZZ8P86A186. Engine No. BKDA48296. It now has 110,000 miles on the clock. The faults that we have had have been codes 19558, 19557 and 17075. We checked the relay number 458 grey one and replaced the number 8 fuse under the bonnet. We then erased all the codes and when we first started it up the engine management light was off. If you then stopped the engine and started it again the engine management light came on. A further scan revealed fault code 19558. We replaced the anti shudder valve or intake flap with a brand new one. The old one I dismantled to find that there was a tooth missing on the gear which had jammed the flap so with the new flap fitted and erased the codes the engine was restarted and after the second start without driving it anywhere it came up with code 19558 again. They then supplied me another new flap which we then fitted but this has come up with the same problem. The car is very sluggish but is not in limp mode. If you hold the throttle stationary at 2,000 rpm the revs fluctuate about 500 rpm. Below 2,000 rpm they are stable. This is a manual gearbox. Both the fans on the front of the vehicle work fine. We cannot find any other faults. This has now been going on for over a year and we cannot seem to solve the problem. We cannot afford to send it in to Audi. I have my own fault code reader. Can anybody shed any light on it.