Car Will Not Accelerate problems of the 2014 Kia Motor Optima

We started reporting issues this past July to our dealership, kia rivergate in madison, TN. They have had our car in three times and keep telling us theres things "we" need to fix. My car is still on warranty and is under a total engine recall. The car started with a knocking sound in the engine and had issues when we would accelerate. The car did not want to accelerate at all causing us to stall in the middle of the highway several times. They told us nothing was wrong but they replaced a sensor. The car continued to knock and stall. I asked them if it was my transmission and they said no, it's fine. They said we could try replacing the battery and they changed the oil (at our expense). The car has had battery replaced three times because they told us that was the issue the first two times. The car has gotten much worse in the last few months. The last time we took it in to them they are now saying that it might be the fuel injector. Once again they are stating that we must pay for it. I've called them because the car had huge clouds of smoke coming out the back and is shaking even worse. Once again they said there's nothing they can do. I told them we are having to add ol 3 times a week with no signs of a leak. My car is only 3 years old and I repeat, my car is still under warranty and is on a recall for several issues including the engine. Now my car isn't drivable at all. It started shaking to the point of throwing us forward in the car and smokes like it is on fire and the check engine light will not go off at all, so you're telling me there's not an engine issue? bullshit. Even a fuel injector would be considered part of the engine because it has to run through the engine to make the car run. I'd like to know why kia is not honoring their warranties or recalls. My next step is to call an attorney and sue kia.