i installed a new 90 teg cable on my b16. i've been having this problem were when i first start driving it the clutch engages at the top but after i have driven it for a half hour it starts to let out at the bottom, almost 1" from the floor. why is this?

 

the thing is last night when i was done driving it was disengaging near the floor. i start it up today and it is near the top again, were i want it to be. but then i go drive it for a half hour and it is disengaging by the floor again. is the cable heating up and the cooling off?
does anyone else's do this?

 

someone has to have an idea