Volkswagen Repair: check engine code P0441 P1136, mass air sensor, emission control systems

Question
bought a 2000 jetta vr6 used with 66k miles. scanned and found codes P0441 and P1136. i cleaned the mass air sensor and replaced air filter. was fine for 5 days and same codes came back. any suggestions on what to do next?  

Answer
With nearly 10,000 DTC's possible, I don't have them all memorized, but I believe the 2 are related this much:  They are both related to emission control systems.  That is to say, they are not specific to ignition, or fuel delivery, just emission control.  With only this much, generic information to go on, I'd have to say that Catalytic converter efficiency, and at least one of the oxygen sensors are to blame.  There is a Volkswagen specific test, which has as many as 20 steps in it.  It is to determine what is called "readiness code."  The readiness code demonstrates to anyone who wants to look at a particular vehicle that ALL of the OBD II emissions control systems are functioning within their allowable tolerances.  Give me the opportunity to follow up with you, pending some further investigation, and I'll give you a follow up answer tomorrow, after I get some homework done on your specific DTC's, and a 2000 2.8L VR6...Is your engine code "AFP?"  Nevermind, your engine code is "AFP!"
"AAA" ended in 1999, and "BDF" didn't start until the GLI release in late 2002.  I'll get back to you tomorrow, Miguel, just let me do some homework, OK?

Don't need until tomorrow.  P0441 is "small leak detected" in the EVAP system.  Furthermore the P1136 is "longterm fuel trim too lean."

I don't advocate just changing parts, but it sounds to me like the N80 valve, that allows fuel vapors from the "canister" is faulty.  Change it.  That should cure your problem.  Before you spend money on a new N80 valve though, make sure your gas cap is fully functioning.  Take it off, and take it a local parts store that can test it.  If the cap tests OK, then replace the N80 valve.  That should keep the "Check engine" light out for a while.
Miguel;
I did some more checking today, and it turns out there may be another reason for your DTC's.  The "Leak Detection Pump" may need to be replaced, but it is a rather expensive part.  The N80 valave is a little over $100.00, and the leak detection pump is about $260.00.  Without being able to hook up a "smoke" machine to look for the leak at its' specific location I can't be more specific thjan that.  I'm sorry I can't tell you for sure that it's the fuel filler cap, the leak detection pump, or the N80 valve.  They all have been faulty, in my experience.  I hope this is of some assistance to you.  Please let me know.  Thanks.