Hello Guys,
Thanks for all your comments. I took my car again to get the rumbling sound checked up, the service manager did ABSOLUTELY nothing, the car now has a new sound coming from below when I step on the gas, he said that he could not do anything and he suggested to wait until the Mazda representative visit the dealership. I asked him when was he going to come visit and talk to us and he did not know when, that he was going to call us when he knew. I called the 800 number and they immediately called the dealer, talked to the manager and 15 minutes later the service manager called me and setup an appointment to have a meeting with the Mazda guy. I don't know what the mazda guy will do, but this has been a nightmare for me. I told the customer care representative at Mazda that I will never buy mazda again and that the dealership service is the worst I've ever experienced.
I'll update you once I meet with the guy.
More than likely, the rep. that corporate Mazda sends will probably be an engineer. So, chances are he can help diagnose the problem and find a solution. Good luck.