2011 buick regal t - problems (belt tensioner/pulley,radio,exhaust smell, turbo,etc)

[manny_3]

I've had this vehicle going on 5 months now & purchased it with 16,900 miles. It now has close to 22,000 & about to do my first oil change. 1st issue, (1-2 weeks into driving) was the radio re-setting itself to factory settings & a squealing noise that would pop up when the a/c was on. They did a software upgrade to the radio which fixed the issue, and they finally found the problem with the noise from the hood which got replaced also (belt tensioner, & pulley). Another issue that came across maybe a week after I picked up the vehicle was a very bad sulfur smell coming from the exhaust, this particular problem has not been resolved because they cannot duplicate the issue. It seems to happen during stop & go traffic when it wants to. I'm wondering if anyone else has had this particular issue & if so what is it? I've switched through every gas company & it seems that it doesn't make much difference. The check engine light came on once and pulled up the code P0299, I noticed that the vehicle was very unresponsive when stepping on the gas, & also had a rough idle at stops. Had to take it back to the dealer twice for them to come up with the issue which was Turbocharger Control Solenoid valve (replaced) & notice a difference in take off, also don't feel the rough idle any longer. The GPS also started to freeze up in the menu for long periods of time, service replaced the radio. There was also a very humid smell coming from the a/c vents every morning or time after vehicle parked which never got fixed. I then started to be more picky on the vehicle & noticed that the screws holding the 2 front doors (galvanized screws) were rusting, which I questioned & the dealership replaced. My main question to any other Regal T (CXL) owner is if they notice a lag between switching the reverse gear into drive? I notice a 4-5 second lag time before it switches gears which to me doesn't seem normal, but the dealer seems to think that it is. Also, has anyone else experience the sulfur smell (rotten egg/firecracker) coming from the exhaust? Sometimes it gets bad enough to where it goes through the a/c vents into the cab. This isn't all the issues that I've had, but are the main concerned problems.