Toyota Repair: 2000 mr2 spyder cel PO171,174,&135, maf sensor, mr2 spyder

Question
Ted,
I have cel codes PO171,174,and 135 at the same time.  I have clean the maf and replaced the air filter.  I reset the cel by disconnecting the battery and it came back after 3 engine starts.  I don't want to take it in and have the process of elimination  about 02 sensors start without having some idea of what's going on.  Thanks in advance for your help.

Gwen G.
Suitland MD

Answer
The p0135 code is triggered by the O2 sensor bank 1 sensor 1 which is in the pipe in front of the car converter. It usually takes a few drive cycles to cause the sensor code and the 171 code to come back.
The p0171 code should be addressed first since it can cause the others. When you cleaned the maf sensor did you clean the patinum sensor wires inside the opening? The small round bulb with the two wires is the air intake sensor and cleaning it only won't help, use only electronic parts cleaner as other cleaners can damge the sensor.
How does the engine run other than these codes, any rough idle or stalling?