[autojoe]

a scan tool is more complex than a code reader and can look at data stream by viewing all sensors as the computer is seeing them.you can not bench test a 02 accurately.....I know before people were using a propane torch and monitoring 02 voltage with and without propane flame.You need to tap into the 02 circuit like I described to see what is going on in the 02 circuit......would have to do this while the fault is happening while the light is on......may be an intermittent problem.the computer has the capability to correct for a lean or rich condition to a certain point to maintain fuel control.no driveability problems.......light since new fuel pump but no light or code before new fuel pump replaced?why did you change fuel pump?