How easily does a MAF become faulty?

[JeremyW]

I have a 2001 996 Carerra 6-speed 72k miles and have been experiencing a slow to respond throttle and then surge in RPMs. Based on posts for similar symptoms, I cleaned the throttle body. When that did not improve the condition I cleaned the MAF using CRC MAF cleaner. This seemed to temprorarily resolve the problem for a day, however, I am now experiencing the surging issues intermittently again. I read a short debate in a post that a MAF does not easily become faulty and that if properly cleaned should resolve most problems. Rather, it is was suggested that replacement of the MAF by users of this forum is primarily out of convenience and is seldom necessary.

Does the MAF on a 996 become faulty? Just wondering if I should invest in a new one if a second cleaning does not permanently resolve my problem or start considering other causes. Thanks in advance for your thoughts -

Jeremy

Edited July 14, 2010 by JeremyW

[Loren]

Disconnect the MAF and drive keeping the revs under 4000 RPM - if the car drives fine you need to replace the MAF,

I am surprised you do not have a CEL.

[wvicary]

I have cleaned loads of these sensors over the years and found it to be a waste of time. If the sensor has a problem from contamination, cleaning it is only a temporary fix at best and you often find the sensor still reads volume on the low side. These sensors fail often or display incorrect readings on all german vehicles that use this type and need replacing with the newest updated part. Having said all that, I'm not sure you have a MAF sensor issue. I would verify that there are no codes then inspect for a vacuum leak and check fuel pump pressure and volume.

[JeremyW]

Thanks Loren and wvicary - I will start by testing as Loren suggests and then confirm codes, etc. as suggested - Jeremy

Edited July 15, 2010 by JeremyW

[JeremyW]

Loren, Wvicary - Thanks again for your thoughts. I unhooked the MAF sensor and although it did seem to improve a little bit my hesitation and surging problem did not disappear. I also stopped by autozone and there are no fault codes stored. I suppose it is now on to vaccum lines and fuel pressure, unless you have a better suggestion. Is there a clear diagram of vaccum lines out there other than the parts schematic? Also, what is the best way to check fuel pressure? I did verify that my fuel filter was replaced approximately 10k ago during the 60k service. Thanks again -

Jeremy

Edited July 21, 2010 by JeremyW