Code P0171 system too lean,check engine on, what it means??

[ReniA4]

hi,its been 3 days that im trying to figure out what is the P0171 system too lean code. I looked up online but all i found is 7 different meanings. The check engine light is on, and the car lost a lot of power and it runs kinda weird. Can somebody from their experience before explain exactly what this code stands for and where i should start! I just cleaned the MAF about 2 days ago and the problem still there. Thank You all. 2004 audi a4

[A4 Maine-iac]

Here is some info on P0171.
http://www.obd-codes.com/p0171
Cleaning your MAF doesnt always fix a faulty MAF. Check all your vac lines as well. Do you have a VAG tool ?

[ReniA4]

thanks a lot for the info. i checked the website,very helpful. i have a VGA tool. dont know how much that would help. it started to show different codes a few days ago,and now its p0171, i havent check the vaccum lines yet. im gonna do that on monday. driving like this for a couple days u think would cause any bigger problems??i never replaced the fuel filter,so imma check that too. i have a k&n air filter so i thought the oil did smth to the MAF. Im confuse because it start showing weird codes like misfire while coils and spark plugs are just fine. 02 sensor was another code. All kinda weird stuff,i just dont know where to start

[A4 Maine-iac]

Running lean you will get misfires. How often do you get the O2 code? That can also be a cause of your issues. Do you have full version or shareware of Rosstech ?
Here is some info on audi codes.
http://www.bentleypublishers.com/tech/audi/audi.dtc.table.htm
Here is a trouble shooting guide.
http://forums.vwvortex.com/showthread.php?2666114-1.8t-Technical-Forum-Guide-FAQs-Tuning-Modification-Assistance-Troubleshooting

[ReniA4]

just an update. i found where the problem was. just behind the engine were a few tubes (forgat their name) supposely they manage the air in the engine, completely melted about three of them. so i got them from the audi dealer the only place that had them for about $150 all. replaced them and the car is running rich.better than ever,full power. i guess that was the problem. We will see if anything comes up later. I will keep u posted and thank you very much for ur help A4 Maine-iac. by the way audi sux on those plastic stuff that has around the engine

[A4 Maine-iac]

Good deal yeah prolly was the breather T in the back. Nice yeah they break pretty eay when they get old.