I drive a 1987 FC3S n/a 5-speed with the following enhancements:

New rotors, calipers, & brake lines
H&K Intake filter
LSD from a 1991 TII
Racing Beat aluminum flywheel
Eiback springs and Tokico shocks
Racing Beat Catback
1991 Aluminum hood
s5 taillights
1991 TII spoiler

It's always the little things it would seem to break... I was showing off my FC, though it's nothing too special to a friend and whilst under the hood, I pulled the throttle and the car gave off it's signature sound. Well when I got back in a bit after that I pressed the gas to leave and it was like there was nothing there. The pedal dropped down about 75% and had just about no pressure at all. I floored it and the car was able to go. I can even go fast still, but it feels like if it were to continue without being fixed it can break something else in that area. I am not sure what happened but it seems like a tension spring might have snapped off but I could not find any loose parts in the cabin. Does anybody know if that is indeed the case? I took a picture to kinda show you what I mean in case I did not explain well enough. You can see that there is the end of the throttle cable followed by a rubber gasket, then about 1/2-3/4 inch of free play before the yellow feed. That space is where I suspect something popped off.

 

check the end by the throttle body.
that area you pictured seems to be ok.

 

Im having this same problem on my 90' n/a vert. Just removed the throttle body housing to replace the tps but now the gas pedal is slack for about 70%. On a possibly unrelated note I just replaced my old blown radiator with a godspeed and its still running hot im going to work on it more tomorrow and hopefully finish solving these problems.

 

Mine had a similar problem, though not quite as extreme, I just tightened the throttle cable and it was fine

 

I just had a pressure leak. My car though, is in a bad state. One or more of the inner o-rings have failed and there fuel getting into my coolant system when its running and it builds pressure in the airpump hose very fast and gets hot.

 

After a few months have gone by I found the missing gasket that popped off and took apart the entire throttle cabling system and tightened it, and put it back together. For now, it seems good as new. Thanks for the help guys.