Check Engine Light Mystery Car Runs Fine, But Why the Warning?

It's been a year and a half since after he disabled the misfire codes, and my car is running fine. I have a 91oct tune as well but I almost ... Once I restart the vehicle runs fine except the CEL remains lit. This has occurred 6 times now over 8 months. They have replaced the ECU and ... The engine control computer can go bad and cause this. Yes, it could be something else, but check on prices. The computer is likely to be the ... Try resetting the computer by disconnecting the battery for 15 mins. Then reconnect it and let your car sit at idle for 5 mins. It will relearn everything. ... Is constantly on: This means the onboard diagnostic system has detected an issue that needs to be fixed. While you can still drive your car and it may seem to ... Most car problems emanate from a faulty/undercharged battery or a poor electrical connection. With a faulty battery, there's bound to be low ... The computer systems in your vehicle work in a continuous cycle. When you fix a problem that was causing the check engine light, it may take a ... Sometimes the oxygen sensor can get covered with oil, dust, debris, or corrosion and simply fail. This can cause the sensor to send incorrect information to the ... The scanner also allows you to clear the vehicle's internal code, which is what triggered the check-engine light. Do that, and the warning light ... The car will many times idle like crap after a reset until you drive it around a bit. After tightening the cap, it still takes a few drives to ...