Codes: P0171 System Too Lean P0440 EVAP Emission Control System Malfunction

First off kudos to all of you here who share tips and experience with others. I'm impressed!

Any thoughts on these codes, which I've accumulated in this order:

P0171 System Too Lean
P0440 EVAP Emission Control System Malfunction

I have had a solid CEL for over a month, just reset it after reading these codes and it came back on after about 10 miles of city driving.

The first sounds like a bad MAF based on reading threads here, but given the second I wonder what else it can tell us, not being an automotive expert myself. Also, is replacing the MAF oneself a gargantuan task?

Oh yeah, 1997 Jetta GL, no mods (that I know of).

Thanks, ray

It sounds like possibly a vacuum problem. Check the vacuum & electrical connections to the evap purge valve, located on the right (car's right) side of the engine bay, behind the air filter. It's a small solenoid with vacuum & electrical connections. With the engine warm & running you should be able to hear it activating, if you squeeze the hose going to the manifold it will pulse. A vacuum leak can cause the system too lean code, not just the MAF.