specs

Hello all....well, bought my first A4 approx. a month ago and I've hit my first snag! Vehicle is an '05 A4 1.8T Tiptronic, Moro blue w/sport package (lovin' it).It has run flawlessly since purchase...put close to 2000 km on it so far, but last evening ran into some trouble.Headed out of town Sunday morning, car ran great all the way to destination..just as I was leaving to return home the "check engine light" came on.After disconnecting the battery for a couple minutes to clear the light, it came on again after a few minutes driving.The idle seemed to be a little off at the time too....everything seemed normal under the hood, so my daughter and I headed out on the trip home.
Trip home went fine, "CEL" on solid , idle seemed rough when we stopped for fuel.When I got back last night, hooked up a small code reader (sry no VAG-COM yet)and got the following:
P0300-Random misfire
P0301-0304 Misfire detected in each of cylinders 1 thru 4
P0171-System too lean Bank 1
P0507-Idle Air Control system rpm higher than expected

I know...these are all generic codes, best I can do at the moment. This morning I cleared all codes, started her up and again got codes P0300 thru P0304 along with a terrible idle (P0171 & P0507 didn't show up, probably as the vehicle hadn't been through a full drive cycle since clearing codes).Cleared the codes again this afternoon, seemed to idle half decent. Took it for a drive, scanned again on return and again have all the codes listed above...seemed to run good on the drive but still something off with the idle.
Sorry for the long winded description, but would appreciate any ideas/opinions on this as to where to start. If I could get it VAG-COM analyzed, would that give me some better information on what I'm up against?
Alistair

jamieta430

coil packs would be my guess.there is a recall on them. so you should be able to go to the dealer and get all 4 replaced for free.

specs

thks for the response jamieta....will Audi replace the coil packs even out of warranty? Alistair

seanf

with the system too lean code and idle higher than expected code you probably have a vacuum leak, thats what my moneys on, check all the lines and the big plastic pieces for the crankcase ventilation for cracking/breaking/missing chunks

specs

Okay guys....think I've got it! Thanks seanf for steering me the way of the vacuum hoses. In the mass of vacuum hoses and check valves under the intake, there is a crankcase bleeder valve assembly that apparently does the job of the pcv valve on later B6's. The small check valve inside this T-fitting apparently is prone to failure allowing constant airflow into the intake manifold....excessively leaning the mixture and producing the terrible idle!When the vacuum line going from this bleeder valve to the intake is pinched off, idle smooths right out!

Late now but will go and get a replacement tomorrow, install it and report back as to how successful this was.
Many thanks to Redfish1's post over on Audizine regarding this issue.
Alistair

Move4Audi

If that's all it is, consider yourself lucky!
When I had my Jetta, I had all those codes on my car, my engine went, had to replace the engine!! (was only at 175K)

jamieta430

sure will i had mine done about 6months ago and i have a 2002 a4 with 160k
worth getting them done anyway even if it is not the problem

specs

thks jamieta, will look into this....Alistair