Engine light and warning light on.

[Chomper]

Yeah, I will probably replace the O2 sensor to see if thats the case. If its not, like you said, it might be time for a O2 replacement anyways. i'll do the replacement and hopefully thats the problem.

Thank you for your help.

Originally Posted by pwpanas

According to the documention, the problem is either:[/list]....OR....
[/list]Simply replacing the O2 sensor might or might not fix the problem(s). In theory, the problem could also be in the wiring or the ecu itself. In other words, it's hit and miss if you start swapping parts without going through the proper troubleshooting procedures. In order to do this troubleshooting properly, you'd need a copy of the TSRMs (Toyota Supra Repair Manuals), and you'd need to follow ALL of the troubleshooting/diagnostic steps for each of the possible trouble areas listed above.

For what it's worth, if you're going to be working on your own Supra, I have to strongly recommend that you pick up your own copy of the TSRMs. They will literally pay for themselves several times over, which makes them an excellent investment.

One last observation: if your Supra has more than 100K miles on it, and especially if it has more than 150K miles on it, and your primary/main O2 sensor is the one that came with the car when it was new, I'd suggest you replace your primary O2 sensor regardless...
Yes, it could be responsible for low idling, due to the likely-inaccurate O2 sensor readings being passed back to the ecu in closed-loop.