hi, i'm new to the audi thing, i just got a 1999 audi a4 quattro 1.8t that is supposed to be chipped and running 20 psi of boost.

well, it ran like it was supposed to until the day b4 yesturday..... my boost normally goes up to 20 psi like it should.... but now the boost won't go over 7 psi..... there were misfire codes, so i changed the spark plugs... the misfire codes never came back but it still feels like its missing on acceleration..... once the boost hits 8psi the engine jumps a little and loses power. also whenever i'm coming to a stop, when i push the clutch in anytime over 10 mph the engine rpm will bounce from 500 to 1000 and sometimes die.....

any help will be useful.... these are the codes that are in it right now....

Tuesday,28,December,2010,12:54:35:46828
VCDS Version: Release 10.6.3 (x64)

Address 01: Engine Labels: 058-907-55x-AEBN.lbl
Control Module Part Number: 8D0 907 557 P
Component and/or Version: 1.8L R4/5VT MOTR AT D07
Software Coding: 06051
Work Shop Code: WSC 09117
VCID: 3D7A3C5B1DF7
2 Faults Found:

18021 - MIL Control Circuit: Open or Short to Plus
P1613 - 35-00 - -
17834 - EVAP Purge Valve (N80): Open Circuit
P1426 - 35-00 - -

Readiness: 0010 0101

 

17834 is the major problem there, it seems. Vacuum related, which is what I was about to say your problem was. Check your vacuum hoses. Check the connector on that N80 valve and replace the valve if need be.

 

thanks for your suggestion.... i am going to check all my vacum lines 2maro when i get 2 coils..... i think thats whats causing the problem... today it started missing really bad and the check engine light started flashing..... scanned it and now it has misfire codes for cylander 2 and 4