The Check Engine Light may illuminate because the mass air flow sensor sends incorrect information to the engine control computer. This can cause a loss of power on acceleration. A failed mass air flow sensor will require replacement.Google+
Car Problem Reports
Lexus RX300 Check Engine Light and Lack of Power Due to Failed Mass Air Flow Sensor
Lexus RX300 Problem
Average Mileage: 127,133 mi (49,000 mi - 201,000 mi)
obd codes P0171 system too lean bank 1 P0174 system too lean bank 2 P1150 AF Ratio range performance bank 2 sensor 1. first cleaned MAF meter at air box with no success. checked air filter, looks new. checked all vaccum hoses for leaks, ok. replaced MAF, reset CEL by pulling EFI fuse under hood, road tested under malfunction scenario, good to go! no CEL. will verify with more mileage to be totally sure.
Visitor, 1999 Lexus RX300, 147,000 mi
This is actually the second time I had the problem. The last time was about 5 years ago. The mechanic replaced the air flow sensor and other minor tweaks as well. Cost was roughly $575 each time.
Visitor, 1999 Lexus RX300, 155,000 mi
slow acceleration, very rough idle. got the maf sensor replaced. somewhat corrects the problem. likely the rear oxygen sensor needs to be repleaced as well.
Visitor, 2002 Lexus RX300, 168,000 mi
check engine light came on. I took the car into Lexus and they fixed it. Code came back Mass Air Flow Sensor
Visitor, 2000 Lexus RX300, 130,000 mi
I had this happen about 1 year ago. Had it replace at dealer. Now they say a rear one is stuck on the exhaust manifold and they have to replace the manifold at the cost of $800 !!! It is at the dealer now waiting for the part - - -
Visitor, 2001 Lexus RX300, 96,600 mi
I have to replace MAF sensor and O2 sensor
Visitor, 2003 Lexus RX300, 58,000 mi