Ok here's my setup: Civic Si with Greddy Turbo kit, turbo, blue box, etc. and Type 24 intercooler. Nothing else is done to the engine.

My car has been running great for many miles but now its doing something weird. When I do a cold start my car runs great. The autometer air/fuel gauge reads as it did when I first installed it before and after the turbo, 1 led bounces back and forth from lean to rich. I drive the car around, get it at running temp still no problems. But after driving about 10 minutes the car changes and the Air/fuel gauge does not read as it did. Several led's light up and illuminate lean and a portion of Stoich all at once. When I start from a stop the car will bog like a mf'er when it does this. I'll hit the gas and it slows down.

I'm getting no CELs, I wish I were then it would be easy to fix. The only clue I have is the weird way the Air/Fuel gauge is acting, other than that I'm clueless.

If you have any suggestions, things I should check, please please let me know. Thanks

 

Since the air/fuel gauge basically displays the output of the 02 sensor, and assumimg the gauge is working correctly, it would seem your 02 sensor is on it's last leg. A bad 02 sensor won't necessarily set a code. The ECU looks for activity from the sensor and will only code if there is none for a certain period of time. Low or slow activity will satisfy the ECU, but it will mess up the fuel ratios.