928S Shifting Problem.
 

My 1986 928S has developed a shifting problem.
Occasionally when downshifting from 4th to 3rd, the shifter pulls back and becomes very sloppy. The car remains in 4th gear and it won't let me select any other gear.
Eventually with some wiggling, pulling up and pushing down on the shifter, I am able to find the gears again but sometimes it takes several minutes.
I consider this a dangerous situation as it is quite unnerving to be stuck in 4th gear coming off the freeway. The problem has also happened when shifting from 1st to reverse when parked.
Any thoughts on this issue would be greatly appreciated. I want to drive my car without worries. Thank you,

Front shift rod ball cup? Rear shift linkage? Not sure, as mine is a 78, and I don't know what might be different on the 86

If you are doing the work yourself, I would suggest replacing both the front shift ball cup and the rear shift linkage coupler (looks like a universal joint) since the parts are relatively cheap and would make your cars shifting feel much better. I did both on my 911 a few years back and the shifting difference was like night and day. No more "mystery shifter".

Definitely sounds like front shift rod plastic cup deterioration. Happened to me on several occasions. Replaced the plastic cup in the front shift rod, and installed delrin bushings in the rear coupler. Definitely worth the effort/money, the shifter is very tight and precise now.