Have you checked your transmission fluid? Make sure it is at the proper level. If it is brown or has a bitter smell you need to get the fluid changed ASAP. Have you checked your oil level, as a minimum make sure it is full, but you should get it and the filter changed soon. When the check engine light is on head on over to a parts store, Advance, Pep Boys, etc they will read the codes for free. Post the codes here for advice on that.