My 1998 GS300 check engine light came on so I had the codes read at the auto parts store. They revealed.
P0100 MAF Malfunction
P0130 HO2S Circuit Malfunction, Bank 1 Sensor 1
P0133 HO2S Circuit Slow Response, Bank 1 Sensor 1
P0171System Too Lean (Fuel Trim)
P0153 HO2S Circuit Slow Response, Bank 2 Sensor 1
A couple of months back I took the car in for service and they replaced an "air flow" sensor. ($45.00 part plus $250.00 labor) I don't have the details for this part. Regardless, the check engine light came on 2 days later. The parts store suggested both oxygen sensors and possibly the MAF.
This car has 115K+ miles and has had very little maintenance, other than oil changes. It is a little sluggish during initial acceleration, but runs ok otherwise. Before I got both sensors and the MAF, I wanted to run it by the experts on the board.
This ad is not displayed to registered members. Register your free account today and become a member on Club Lexus!
I think you may have bad O2 sensors and bad air flow meter. I suggest you go to the Lexus dealer and ask them to look at the O2 waveform and look at the short term and long term fuel trim( for code P0171). It's rare to see all these codes at once, but it's happened.