1997 Acura Legend mileage: 122,000. Problem: engine runs very rough for about 5 minutes after start-up and then all of a sudden it runs fine. Doesn't matter if I've driven 2 miles or 200, if I shut it off and restart it, it still runs terrible for the first 5 minutes. I've changed the fuel filter twice, and the plugs are good. I had a mechanic check it with a diagnostic unit, and he found no codes showing. Any ideas?
Have your car scanned again. The "check engine" light will "light" when there is a malfunction in the engine management system. The fault code is then stored in the computer. The computer must be scanned to retrieve these stored faults to pinpoint the malfunctioning component. With a code scanner you can check for fault codes to find out why the light came on in the first place. You can clear your cars trouble codes after you make the needed repairs.