its wiring...i stated this before. your cel came on...then you noticed the tah reading a diffrent measurement then what you noticed before. its not the tach...its not the o2 sensor. you have some wiring bugs that you might want to explore first. my guess would be this since you probaly arent throwing a code anymore correct? look up how to put a b16 into your crx.....follow all the wirring diagrams. sorry to be a moron towards you...but sometimes these questions are just dumb