Ok so it wont pass emissions. It has a gassy smell and a rotten egg smell. once heated up the s light flashes the idle fluctuates. Then the check engine light comes on.. Te car runs perfect other than that. Almost like brand new. HELP!!!!!!!!! and hello everyone

 

The check engine light and the S light flashing means there are error codes stored on the engine and transmission computer.

You need to get the code(s). Follow the instructions in the DIY section on how to get CEL codes. Count the CEL light and then the S light flashes. Let us know what each light blinks.