The B16 in the rex I just picked up is running very, very rich (smells like a gas station everytime it runs, showed a 1/8 tank gone after 20 miles). I'm trying to locate the problem here before I have to go through emissions. I'm thinking the O2 sensor may be bad, but I'm trying to rule out other possibilities before I buy another one. The factory manual says to read voltage while you full throttle accelerate, which is a little hard to do with a multimeter. Any other checks/tests or possible other causes anyone can name?