Finally was able to capture OBD1 (93sc400) error codes via manual E1 ,TE1 jumper wire
test during a come and go problem with car performance.

Come and go problem going on for several weeks but this time I was ready and had jumper
wire in place and the following two codes showed up:

1) code 24 MAF sensor

2) code 31 IAT sensor

Could one of the two bad sensors cause the other to show fault when actually it is ok??

Which one should I replace first in case the other may be ok??


I'm thinking MAF...any opinions??

 

Yes, the MAF/AFM sensor is probably causing the second IAT sensor. Replace the MAF and the IAT ASAP. The MAF sensor can cause all kinds of idle issues including complete shut down at stop lights which gets annoying. Just buy a used AFM/MAF from the club lexus sale forums.

 

Maintenance issues go in this forum. Moved.

 

https://www.clublexus.com/forums/per...o2-sensor.html

I just went through this whole thing for a couple of weeks and finally got it solved. Test your MAF first if it's good or bad. It could be a number of things causing the problem. I followed this guide to fix it.

https://www.clublexus.com/forums/5728985-post5.html

 

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 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
at the bottom. Anyone have any comments re the test I ran or as to the unit listed below working
as a replacement sensor??

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