Teh SES light (service engine soon) could be from a loose gas cap. Like when you add gas and dont tighten it three or more clicks.

I would take it to the dealer. Around here they charge between $42-$68 to do a full diagnostic test. They have the best test equipment, the best trained personal, and will be able to give you the most likely source of the problem.

 

Like blazmaneaxx i too cleared out my rattling cataylic convertor,now it is louder and it takes a bit to shift between 1-2nd,and when it does it leaps forward to harshly..would anyone here risk buying a used cat-convertor??

 

Not for the cost of a new aftermarket converter.