i have a 2001 jetta 2.0l and i was getting cel code p0171 and read that my factory bosch maf was probably bad and that it was a common problem so i got a new one. when i put it in, the car does not run right at all. it barely idles at about 300 rpm and when i get up to about 3000 rpm the epc light turns on in the dash. if i take off the intake between the engine and maf it idles fine. if i unplug the maf it idles fine. i didn't have this problem with the other maf. any thoughts on what is going on or what i should check???

 

allright i put the origional maf back in and it works the same as it did. idles fine and doesn't lite up the epc light so it is deffinatly something with the new maf sensor. it throws that code probably everyother day. i only drive to work and back which is like 10 miles, 15 minutes, each way

 

when i blow into my origional sensor the engine dies if i do it long enough. not sure what this all means. does that mean that my new sensor is bad and my origional is bad. what else should i check for?

 

I've experienced the same problem with my 2001 2.0 L (gas) Jetta. The MAF (Mass Air-Flow Sensor) has been reporting bad, though a P0171 code. I got a brand new one, installed it, cleared the codes and took it for a test-drive. 15 miles, restarting about 4 times along the way, everything was fine.
Then, on my way down the highway on the very next trip, my EPC light came on, and the cars started stalling out. I eventually could not get it to stay on anymore. It would start up fine, but then as it was about to idle, it would just cut out.
I installed the old "bad" MAF, and was able to drive it home. I guess I'm going to have to take it to the dealer, but that stinks. I wish they would just issue a recall on this, since it's such a well-known problem.

Does anyone have any other ideas? Did anyone manage to get this fixed?

 

So I took it to the dealer, they (said they) replaced the MAF sensor and the wire/connector to the MAF sensor. 20 miles later, check engine light is still off. (However, they did manage to break my driver's-side door hinge, such that the car beeped for about a minute as though the door was open, and the driver's side door-light wouldn't go out without disconnecting it. They'd better fix it at no cost to me.)

 

I have an 01 Jetta that tripped the EPC light the other day. After doing a good bit of research on other forums, someone noted it could be the throttle body (close to the MAF - on the other end of the shared air hose) carbon builds up and doesn't allow the butterfly inside to rest properly. You usually notice an idling fluctuation when still. Its not hard to take out and clean yourself. At the very least you gain some lost power back after years of build up.