2005 FORD TAURUS WITH 43,000\r\nMILES...ENGINE

Hello Sir, Check Engine Light ( CEL ) most usually means that something is wrong with the Emission System. It also indicates that the O2 Sensor needs a check. But this light doesn't come up on its own. Kindly take it to a AutoZone, they will scan the computer and will retrieve the error code. This code will then can be diagnosed for repair.
Kindly take it to a Service Center and retrieve the codes and give it to us and we will diagnose it and give appropriate solution.
Thank you Sir, Have a nice day.

The check engine light comes on when emissions will exceed 1 1/2 times the federal guidelines. The flashing is an indication of a cat damaging event (misfire). Are you sure you tightened your gas cap (will set an evap error code if loose). O2 sensors are more reliable than given credit for being. But they are a good profit point for selling unnecessary parts. I was a California Licensed Smog tech for 21 years and good O2 sensors get replaced way to often (not by myself by the way).

There are two types of check engine lights one is amber it is a service soon, if the amber check engine light starts flashing on and off all the time it means a misfire that will damage the Catalytic Converter and could cause multiple problems.
If it is a red check engine light that means Do it NOW do not DRIVE. Check oil levels and fluid levels.

I think the problem is from the Emission System, something must have gone worng with it. and sometimes it is necessary to check the O2 Sensor as well. But it will be better you scan your car with the computer and so as to know where the problem comes from, so the error code from the scanning will now indicate the repair to be done on your car. Kindly take your car to an Auto Service Center to retrieve the error codes and then ask then to repair it for you or you forward the error codes to us so as to know the best repair to be done on the car. Thanks