today when I was going around 45-50 in 4th gear I went to downshift to 3rd because a light was coming up and I pushed the clutch in around 1700rpm's still in 4th and down shifted into 3rd and when I did the rpm's just went dead and stood around 1000-1200 rpm's and acted like it was in neutral. I was trying to go into 3rd doing around 37-40mph and it just did nothing. It def. did not do what it does downshifting from 3rd to 2nd where it jerks a little and then slows down.....whats the deal here???

P.S.
When I downshift from 3rd to 2nd I downshift around 1700rpm's also with no problem. Also driving a 99' 5spd stang low miles.

 

Either your clutch is slipping like crazy (to the point where the car isn't drivable) or you weren't fully in 3rd gear. Sometimes you can get locked out of a gear depending on your rpms. I usually tap the throttle between gears when downshifting to compensate for the new RPM at the lower gear.

 

I dont think its slipping...everytime I drive it catches every gear with no slippage. Anyone else have any ideas?