I noticed that recurrence of my poor performance usually happens when car has sat in sun or
in hot garage. This morning the car started and ran normally. I removed the MAF sensor and
heated the sensor element with a hair dryer, replaced and immediately started car. Guess what....
the erratic performance showed up just as before. I let car sit for an hour and the car started
up normally. Repeated the hair dryer treatment and bad performance again. I am convinced
the unit is faulty as suggested by the retrieved error codes 24 and 31. I also read that if the
sensor connector has 5 pins, the the unit is both MAF and IAT combined which clears up
the 2 error code readout.

I hate beating this dead horse but MAF's are very expensive new. I can't find a used one on
this forum as suggested by another member. I found a new one for around $150 at the web site
below and the sensor is supposed to be compatible with my 93sc400. The body of the unit
looks exactly like mine but the sensor element looks different. No silver wire or little bulb on the
bottom of mine. Anyone have any comments re the test I ran or as to the unit listed below working
as a replacement sensor?? Laying out $450 or more for a new OEM unit and later finding out that
the diagnosis was wrong would be very depressing.

http://www.ebay.com/itm/New-Mass-Air-Flow-Sensor-Meter-MAF-for-Lexus-SC400-Toyota-Supra-2220442011/251302746649?_trksid=p4069.m2059&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D217033092018778137%26pid%3D100039%26prg%3D1011%26rk%3D1%26rkt%3D4%26sd%3D251302746649%26