I finally completed my intercooler install the other day and I finally got a chance to fire up my 2jzgte vvti swap into 98 gs300. At first I didnt hook up the tach wire. When I started the car, it idles really smooth and nice, but all kinds of lights were triggered on my dash such as headlights, low coolant, and VSC. As I rev on the gas, it slowly gain rpm but then slowly just die off. It was really unresponsive with the gas pedal.

I couldnt figure out what the heck was going on with all my troubled lights. So yesterday, I decided to finish up the tach wire and fire it up again to see if anything changes. Well a few things happened:
1. The rpm guage is now working. This is obvious.
2. Headlights and low coolant lights are gone. VSC is still there, which is normal.

But here are my new problems:
1. Engine revs high now...Id say about 2k rpm and even when hot, its still reving at about 1800 rpm.
2. Engine light is constantly on. Even when I disconnect the battery. The moment I turn on the car, the engine light comes on.

Few notes: I do not have a downpipe hooked up. Its running straight out of the stock turbo's flange with O2 sensor connected at the end.

Here are my questions:
1. Can I read the trouble code by jumping the TE and E like the USDM ECU's?
2. Something tells me my O2 is bad, if that is true then could it have caused my high reving? But then again, why didnt the ECU trigger the engine light when I started the car without the tach wire?
3. Because I do not have a downpipe and the O2 sensor is sitting right at the end of the turbo output flange, could this cause a bad reading as well? Since outside air might interfere with the exhaust gas?