Hi, I have a 2014 Mustang GT/CS. There is a popping noise coming from the right rear side. When I first heard it I thought I had rolled over something and the tire had popped , but that wasn't the case.
It doesn't happen all the time, but when it does happen it is on acceleration. I will drive it for weeks with no popping but today it happened today 3 times in a short period of time. My son says it only happens when it is sport mode.
Thanks for the help

 

Only way to know is to get it up on a rack and start poking and prodding at the suspension. You'll find it pretty quick, I'd imagine. Get a crow bar/hefty pry tool and start mushin' around the connections for the axle, sway bar, etc.

Not sure why sport mode would change things, unless it changes the shocks in some way. Sport mode is for steering and traction control, right? The ABS is turned off or down, so it's not a caliper buzzing on and off...

I could go into detail, but the end result is this: Power applied, car squats in back due to power transfer and axle twist. Upper link, lower control arms, sway bar, shocks are to be checked, ostensibly on the right side.

Car squats due to above, axle will attempt to shift to the left side of the car because panhard bar is the left-right center system. Check that, and it's probably the right bushing if it's that.

If none of that pans out, check the wheel bearing, wheel, and brake caliper. Maybe you have a loose lug nut. Since you seem to indicate it's that rear right wheel and nowhere else, it's not as likely to be the differential... but it could be some other interference in the area, like a muffler movin' or the hangers banging around...

You might also stick a gopro or such under there and see if you can visually identify what the issue is.

You might need to have an alignment rack inspection so the car's at ride height for that check, then you'd want to have a lift inspection for the unloaded suspension check. Two results can happen. Of course, you can do this on ramps and jackstands in the garage, just more work to do it that way.

These are all semi-edumacted guesses. Could be something else of course, but I'm not sure what... Still, I hope that helps, and welcome to the forums!