NHTSA Complaint #11592759 — 2017 FORD EDGE

2017 Ford Edge was rattling with starting it in the morning. We received a backdated letter about a flexplate recall. We took car in to check it out. Service guy said to go home, “you would know if it was the flexplate”. Then car was rattling a little more and check engine light came on, so I brought the car and the letter back in and same service guy said he would check it out. Charged me $764 to change out 4 spark plugs and an ignition coil. Said car was fine to drive and that they checked all cylinders etc. But they were going to ask for Ford approval to replace flexplate….. They called that it was approved and they kept car for many days and said it was fixed. Last week (two months and only 500 miles later), check engine light came on again. We took it back to Auto Nation. They kept car to evaluate the problem. Called us a few days later saying we would need a new engine for $8,500. Service guy said this happens a lot. Most people had traded in for new cars. One guy with extended warranty got it fixed. We asked if cylinders, plugs, etc were fully checked 2 months ago, why would you say cylinders are corroded now? Did fixing the flexplate cause the problem? We looked online and saw talk of class action lawsuits, cylinder issues, Ecoboost engine issues, and possible car fire issues. This caught our attention as a huge safety concern. We are not sure how to proceed. (I have all paperwork from Autonation and recall letter.)