One problem related to gas recirculation valve (egr valve) has been reported for the 2011 Buick Regal. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2011 Buick Regal based on all problems reported for the 2011 Regal.
I have owned my Regal since 2011. As I accelerate the car would shudder and shake, then I would get a service stabilli trac message followed by a message stating that the engine power has been reduced. After I have the issue it will reset itself after restarting and then will run fine for a while. I called on star on several occasions and they told me that it has an engine misfire or the stability trac needs to be serviced or the electronic throttle body is malfunctioning. I have taken the car to the dealer and they tried to fix without any luck. I think part of the trouble with fixing it is the fact that the computer resets itself and therefore they can't find a code. The other issue with trying to fix is the fact that the car only has the issue when it is 35-40 degrees outside and below. Other issues I have had, driver's seat heater not working, outside trunk release not working, passenger side seat belt does not connect properly and of course the recalls for the driver's seat bolt and exterior turn signals. Now for the bad news for myself is that the car is out of warranty. Given the fact that I have read many similar complaints and most of them not being resolved, I find it very hard to bring myself to take it to the dealer and have them guess to what the fix may be at my expense.