I have a 2000 RX300 with 62,700 miles. Two days ago, I took it in to replace the front brakes and "D" bulb. One day later, the Check Engine light went on, which never happned before, so I returned to my mechanic thinking that they might had inadvertently dislodged a sensor. The diagnostic code read P0171 and they ended up replacing the Air Flow Meter for $250. I understand that this might be a common replacement but after reading some threads on this forum, I was wondering whether the faulty reading had to do more with my installing a K&N filter two weeks earlier? Sounds like I should had just cleaned the MAF sensor with a carburetor cleaner.

 

Yes no need to replace MAF, clean it first. K&N should not affect MAF unless you over oil it.

 

https://www.clublexus.com/forums/sho...highlight=fern

Check out the link to a previous MAF sensor discussion.

I also had a check engine light issue when I installed K&N on the BMW, but after disconnecting the battery for 20 minutes (this resets the ecu)...

I also cleaned the MAF sensor with electrical contact cleaner - the non residue type, when I started up the car the check engine light didn't come on anymore...

***It would be interesting if your mechanic still has the MAF sensor and if you re-install it after disconnecting the battery for 20 minutes, if you still get the check engine code...?***

Check out this link to K&N regarding reseting the ECU
http://knfilters.com/faq.htm#6

Cheers,
Fern

 

Brake dust cleaner works well, too.

Another bit of advice. Before I ripped out my airbox and did some air mods to my car, I also had the K&N panel filter.

After one MAF problem, I washed the K&N filter and then reoiled it on the side facing the air flow and this seemed to keep the dirt down (and I live in one dirty city).