My check engine light comes on after the car warms up , if I shut it off then restart it goes out then comes on after a few minutes , codes read O-2 sensor's , temp sensor, egr , which I replaced about 11 months ago...I have no cats & have the Mac power chamber exhaust, the exhaust tips look like she is running a little rich, she is idling OK & at 170,000 still burns no oil , I erased the codes twice but soon as it warms up on they come....any tip on what to try ????????? Thanks much.............................. Johnnyboy