I have done a search for similar problems and not really come up with anything so here goes.
Came up to an identical car at the lights the other day (2000 S3 8L chassis). His car absolutely blew mine away, whether it was standard or not i dont know. Any way it didnt help that at 5000 revs in second on full throttle all power cut for a second then came back. no faults on the dash and only the fault code below after a scan. Ive read about the secondary air injection being for emmisions and some people actually remove it so i dont think this is related, unless you guys tell me different.
A couple of days before this i was checking under the bonnet and found the vacuum pipe from the inlet manifold to the FPR was totally split so i replaced with a silicon one.
Has any one had this problem before, it didnt sound like the boost was dumping, more like the fuel had been cut. The car also does not feel nowhere near as fast as it should, it is only standard and 13 years old but still id have expected more and not to be so humiliated off the line by an identical car even if it was modified!
Overall the car seems to run fine. Any ideas where to start looking. the only modification it has had is the valve that sits on top of the rocker cover has been bypassed using a guide that was from this site but that has been like that for a year. I'm still thinking boost/vacuum leaks but at a loss where to check next. could the wastegate actuator be weakening? i'd have thought i wouldnt get any boost if this was the case though.
Any pointers would be greatly appreciated.
1 Fault Found:
17840 - Secondary Air Injection Solenoid Valve (N112): Open Circuit
P1432 - 35-10 - - - Intermittent