I recently replaced my 97 which totalled ( not my fault ) with a 99 2.3l 5 speed.
When I got it. It had a o2 sensor 2 code. I replaced the sensor. Erase code with scan tool. Same result o2 sensor 2 code. I run tests on the sensor and wiring. I find 13 volt to the orange and blue with the black and yellow. With engine off and ignition on or in the ii position the green and black confirms ground but i get nothing from the red and white. So i do a continuity check and confirm continuity to each wire in the harness and trace the black and yellow to a relay and confirm the relay operates. At which point i deduce that my ecu ( which is getting full continuity to each wire relating to o2 sensor 2 with unnessicarily new oem components ( relay o2 sensor ) ) is no good. I call a refurbish company and they say they cannot repair this problem in the ecu. So I find a used Ecu same part number from a 98 2.3 5speed. With the battery removed for other reasons i change ecu then pull the 7.5 amp back up fuse. Then install and connect battery, wait one minute, replace the back up 7.5 amp fuse. Turn it over and nothing. Seems like no fuel delivery. I go back to salvage and exchange the ecu. Again same part num. this time from a 99. Repeat install process. Same result. Anybody got anything on this? I can go and plug in the old ecu and it will start right up. No reset process. Everything is original other than maintinence no work has been done that i can tell other than some screws holding the mirror on. And I know i work in collision and have had it on the lift.