I have read a million post on pulling codes by the blue plug with a jumper. I have a 91 wago with 1.5 2wd. So here's my problem. While driving the light will come on. I turn it off to check codes, it seems like the codes are reset. Am I doing this wrong or what? My problem with it is that I will lose power while driving. Even with the cat off. I replaced the map sensor, new fuel pump and filter full tune up. The only thing i can come up with is maybe bad o2 not reading enough fuel. Only getting 30/31 mpg thanks for all the help.