Some times some driving may be required to get a particular symptom to resurface. It sounds like they might have only been starting it.
This may be a known problem actually once you get to the dealer. There is a service bulletin that related to a starting issue and the EML light. The bulletin states that this may be either the throttle (eml) electronic throttle, or the wiring harness for the engine. In most cases it is the throttle motor that needs replacement, but in some instances I have seen the engine harness needing replacement as well. This is usually an intermittent problem but it could leave you stranded. Once the dealer scans the codes, they should be able to help identify if you will only need the throttle.
I hope this information is helpful. Please accept and best wishes on your repair. Thank you.