Good morning :) We recently bought a 2005 Acura

Good morning :) We recently bought a 2005 Acura MDX and have three concerns with the performance of the vehicle: 1). There is a click or grinding noise that I hear and also feel under the gas pedal only once when I start the vehicle and start to drive. Is this normal? I have heard that it is the ABS initiating, however why do I actually hear and feel that? Seems that when the car was new, it must not have been noticable. 2). There is a whining sound at higher speeds when I apply gas and then when I let up, it goes away. What could be causing that noise? 3) Lastly, the car seems to spudder, run a bit ruff at times, usually between 30-50 mph or even at higher speeds but mostly when you start to slow down and take yoru foot off the gas. Again, just wondering if you could provide any advise of what these problems could be associated with. Thanks in advance for your technical expertise. Have a great day.