,l have a 1994 Lincoln Towncar, it makes a loud poppingsound coming from the passenger floorboard.l had a garage check out the tierods balljoints a frame bushings and suspension also the pads and calipers all was ok . It is mostly noticeable on turning or stopping, also it is worse with a passenger in the car . Anybody have any ideas.

Find a garage that will do a really good lube job most fast lube places do not understand about doing a lube job and when people do there own oil changes they car does not get lubed so its possible this car has not had many lube jobs. Most cars do not need lube job because they have rack and pinion for steering so its just something that gets missed.

It sounds like either a seized ball joint or a body mount. The usual ball joint check wo not pick up a seized unit. You have to disconnect the outer tie rod and manually move the spindle left to right. The only other thing that could cause the floorboards to clunk is a broken body mount at the frame just between the fender and door.

Check the passenger side rear subframe to body mounting bolt and nut. It was a recall to replace them due to corrosion eating through the bolt and nut and causing the subframe to come loose. This can cause the subframe to bump or rub the bottom of the car when turning.