Code 43, can't figure it out!!!
So i have been dealing with this problem for about 6 months. I am getting a code 43 in my 91 GS teg b18a1 OBD0, In my manual it says that it is a an oxygen sensor problem or a vacume leak. I have noticed a loss of power. When i am driving around town the CEL does not come on but if i am above 3000 RPMs for over a minute it will come on. So far I have replace the Oxygen Sensor, Vacume Tubing, Fuel Filter, checked all my grounds. Could my ECU be bad? How could I check? Please help.