99 ls / I added a bolt-on test pipe to my setup this weekend cold air intake, headers catbakc exhaust cam gears, and clutch. The car is running good, and fast, but after a few hours driving the car with the test pipe, my check engine light came on. Since i got the car 1 year and a half ago, the light has never came on. I know it is from the O2 sensors because of the high flow fuel because the car is confused with no cat. But what is funny ever since the check engine light came on the car has been running crazy fast. Down low and even more up top. I lost nothing, but gained a lot. Mayve that is because I have an RSR ex mag. Someone told me i could get wideband o2 sensors to fix the check engine light possibly. Also I plan on adding an apex afc to tune the car. WHat do y ou guys think