Ok, my "new" Passat (2002 B5 1.8T - 41,000 miles) is starting to give me a headache.
I did my first service (air filter, plugs, M1 Synthetic 0-40 oil, & filter) to it about 3 weeks ago (BTW-Thanks for all the helpful info on how to do it and what to use). Friday evening my CEL (Check Engine Light) comes on while driving to dinner.
Saturday morning, after reading up about what it could be in the forums, I took it over to my local Advance Auto Parts (like an AutoZone) store and they pull a P0171 code on it and they tell me it's probably the O2 sensor. They guy reset it for me and said if it comes back on then I should come back and buy one. The light was out the rest of Saturday and Sudnay but of course on my way to work yesterday it comes back on again. I went to the parts store again and it's the same code. The girl that worked there didn't know squat and the other guy there said it could be anythign and suggested taking it to the dealer or a mechanic.
From what I have read, I think I should;
1) start with cleaning the MAFS (can you tell me exactly what cleaner to use?)
MAFS cleaning (multiple pictures)
and if that doesn't clear it then,
2) replace the 4 vacuum hoses (they looked fine to me)
HELP with VAG code!!!
and if that doesn't fix it then,
3) replace the O2 sensor?
Does this sound like a good plan of action or should I just take it to the dealer (under warranty) or a mechanic?
I bought this car becasue I thought it was going to be reliable....
P.S. I have slowly noticed a decline in gas mileage too.