Hello, welcome and thanks for asking your question. My name is*****'m a Certified Auto Technician with 28+ years experience. I will do my best to assist you. please keep in mind that I may need to ask questions of you before I can answer. When you reply please feel free to add as much detailed information as possible pertaining to your concern.
Did they show you a fuel sample of the "Dirty Fuel"? If the fuel was in fact contaminated, it is very likely that damage has occurred to the fuel system. Fuel contamination is a major concern with this engine. Especially if it was driven for any distance since the bad fuel was added.
At this time, I HIGHLY recommend to get it back to the same dealer ASAP. If you continue to drive it, it's possible that further damage can occur. I have seen water contaminated fuel cause a fuel injector to stick open and burn up an engine in less than 30 seconds. Of course, fuel contamination is NOT covered by warranty and if the engine fails due to this issue it could cost you to the tune of $18,000 or more to replace the engine.
If you are on a trip and away from that dealer, at least stop at a dealer somewhere during your trip and have it looked at. Make sure that they scan for codes and also don't forget to explain the situation to them regarding the fuel contamination issue so that they will have a much better chance of getting this fixed properly the first time around, otherwise you may end up returning back repeatedly until it's figured out...
If you can post any codes that they retrieve here, I'll be glad to give you a "Second Opinion" on the dealer technician's diagnosis.
Keep me posted and let me know if you have any additional questions...
If you need additional information, don't hesitate to ask, I am happy to help as long as necessary to help solve your concern. Remember, a "Positive" Rating will not close this question, You can post a reply here whenever you want, even after rating my answer!