my car is a 2.3 and other than an idle problem, it seems to run fine. When the engine gets to normal operating temperature, the check engine light comes on.. What may the problem be?

 

It could be nearly fifty different things. You will have to have the car tested. You could buy a book like the "E-class owners bible" 86-95 and bench-test "some" basic components yourself, if you are mechanically inclined, and up to the job. Sometimes it is a major component that you can bolt-on, but other times it be a fine-tune adjustment that requires the mother-ship etc.

Blue

 

thanks for all the replies, i just purchased the book on ebay.