Other Fuel System Fuel Injection System problems of the 2007 Chrysler 300

I purchased a 2007 Chrysler 300 in 6/2/07 as a demo model with 954 miles on it. On the way home from the dealership I noticed a rough idle and also a vibration in my front end while maintaining speeds at around 45 mph. I had to put the vehicle in for service on 06/11/07 and it took until 6/21/07 to get it back. The front end vibration was caused by a bad torque converter, however once driving my vehicle I noticed the rough idle hadn't been repaired. Then on 5 separate occasions when going from a complete stop accelerating to get up to speed, when the vehicle should be going from 1st to second gear the engine just wines and it takes approx 10-15 seconds to kick into gear, making it extremely dangerous especially when merging into traffic. I turned it back in for service on 6/3/07 and as of today they still don't know what the problem is. They have had a field service engineer from Chrysler come in to look at it and he doesn't know either.