ect
 

anybody no where the ect is located? and is true that it can cause a rich condition?

Yep. I once had an ECT (not on a supra) read -40 degrees all the time when I checked it with an ohmmeter. That would cause a severe rich condition.

Ok go out to your supra and look at the thermostat housing. You see what the thermostat housing is bolted to with those 2 10mm bolts? Thats the water outlet housing. You see those 2 sensors behind the power steering reservoir? The one on top has a green sensor connector and the body of the sensor itself is green, thats your ECT for the EFI.

Its a dealer only part and will run you around $70.