MAF and Circumstance

Occasionally, when I’m driving a bit spirited or enthusiastically, two warning lights will illuminate on my dashboard. The “PSM Off” and “ABS” warnings aren’t normally lights I should see while driving. However, when I turn off the car and return to drive again, the lights are off as if nothing ever happened.

It’s not every time I punch the throttle, but frequent enough to cause a tiny bit of concern. I posed the question to Rennlist and Renntech, which are two excellent forums for Porsche owners. There were a few different responses, but overwhelmingly the members of those forums suspected the MAF Sensor.

The MAF (Mass AirFlow) Sensor measures the amount of air entering the engine, and is critical to engine performance, good gas mileage, and low emissions. I’ve noticed my gas mileage has been pretty terrible, so it’s really starting to make sense that the MAF could be bad. I decided to take the car to my mechanic and have him assess the issue.

I only take my car to RMG. Bob owns the place and there’s two mechanics that work there, both named Dan. RMG only services Porsche, and between the three of them, they have more experience than most Porsche dealers at repairing these cars. Bob has been working on Porsches for damn near 50 years, whereas one Dan has over 30 years experience and the other Dan has right at 30 years experience. To tidy up the package, Bob’s wife Linda handles a part of RMG as well, and she has close to 40 years experience with Porsche parts. However, it’s not just the experience and high quality work that keeps me coming back, it’s the honesty and integrity.

Dan ran a diagnostics which did return several errors, and these errors did point to the MAF being the potential issue. He asked it I had done anything to the car since I owned it (which had only been 4 weeks at the time). I told him I had only replaced the air filter with a K&N air filter. He looked very displeased with me about that.

K&N air filters are good filters, they have a reputation as one of the best in the business. However, K&N filters are “wet” filters as they are coated with a thin layer of some type of oil. They’re designed this way so you never have to replace them, only clean them. However, this wet filter design is known to contaminate the MAF on the Porsche 996 (possibly others too). I did not know this. Dan recommended replacing the K&N filter with a regular, normal dry filter and get a can of MAF cleaner to clean the MAF. After I do that, if the problem still persists, then I might look into replacing the MAF itself.

I did a little research and found the Porsche MAF (part 996-606-124-00) would cost anywhere between $537 and $904 depending on what Porsche parts reseller you buy from. Bosch makes the Porsche MAF, and Dan recommended replacing it with the Bosch (part 0-280-218-009) as that’s what they use. I can purchase the Bosch part as low as $180. The installation is crazy simple too.

This morning I replaced the wet K&N filter with a normal dry filter and cleaned the MAF. I’ll take the car out for a spin today and see what happens. It’s nice to know that if I do need to replace the MAF, it will only be a sub $200 job that I can myself, instead of an $800+ job that has to go to my mechanic… even though I do like visiting my mechanic!