NHTSA Complaint #11595397 — 2018 HYUNDAI ELANTRA

About 4 weeks ago (mid-May) I was driving in stop and go traffic on a major highway. My car is a 2018 Hyundai Elantra, manual transmission. After about 30 minutes of this, the car started to just cut out, the engine cut out when I was changing gears. It did this about 6 times on my drive home. I noticed that when the rev meter got below 1, the engine would just stall out, so I tried to give it gas to keep the revs up. In addition, the engine was making a knocking sound. I took it to my mechanic's the next day and when he heard the sound, he said it needs a new engine. He has had a few customer's with similar issues with their Hyundais. He told me to tow it to the dealer and they would help me get the engine replaced. That same day, I had it towed to a dealer nearby. They charged me $195 for a diagnostic and said it needed new spark plugs and replaced cylinder 1 coil, which they did. ($900) I picked it up, but I could tell it still wasn't right. The mechanic assured me he fixed it. However, they also told me the "check engine" light was on (it wasn't). When I was driving it, it started to stall again when I was changing gears. I brought it back to the dealer, he told me his mechanic had trouble getting it into reverse, there was a problem with the clutch. He would need to "tear down the transmission" for $2,000 and even then, he wouldn't know what the problem was. This just didn't feel right--I got the impression they didn't know what they were doing and that this mechanic couldn't even drive stick. I took it back to my own mechanic who couldn't find the problem. He told me to drive it around and when it makes the sound/cuts off, to bring it back. I drove it home--today--and the knocking sound started after 15 minutes. I recorded it and texted it to my mechanic. He called me and said "it's the engine. the dealership mis-diagnosed your problem and overcharged you." I called a different dealer, got an appointment for next week and must play the $200 diagnostic .