Manual Transmission - Shifting troubles... Slave Cylinder? HELP

A couple months back my shifter started getting really stiff, to the point where I could not get the car in gear so I took it to the shop. Well they replaced the slave cylinder and this fixed it for the most part. The car seemed ok but then I noticed whenever I got on the gas hard, the clutch would loose pressure. Driving the car normal, everything seemed fine, but anytime I wanted to hammer through the gears, the clutch looses pressure and I end up grinding gears...Once I get the car in neutral and pump the clutch, its fine again.
So I took it back to the shop a couple days ago, they told me it was the master cylinder, so they replaced it.
But still the exact same problem.... So now Im pissed off because $300 later for the new master cylinder and the labor, still the exact same problem..

Ive talked to some friends and they have all said it sounds like the slave cylinder. Even though its new, its possible that its already shitted out...

What do yall think? And how should I handle it from here on out with the shop? My car is still up at the shop now, just waiting to figure out what to do next.

Anyone...?
I have to go to the shop first thing in the morning

Stock clutch in there still?
Have headers on there or anything?
Had lots of stock clutches cause this problem, the pressure plate cannot hold & this is the result.

Stock clutch in there still?
Have headers on there or anything?
Had lots of stock clutches cause this problem, the pressure plate cannot hold & this is the result.

:stupid: especially if the slave and master have already been replaced and it's been bled properly with new fluid.

Thats what I was wondering... The clutch was replaced about 20k mi ago... I was wondering if it might be the pressure plate... But a couple people said it sounds like a bad slave

Stock Manifolds

Stock Manifolds

If they are stock manifolds, then I'm definitely going with pressure plate if it's still a stock clutch (even if it was replaced). I believe he asked about the headers because it's a known issue that headers can heat up and boil the fluid in the braided master line where they come close to touching, and a resolution for this is the wrap the line with heat resistant tape, hose, and/or other materials, along with using a high temp fluid, like DOT 4 brake fluid. If you have stock manifolds, you shouldn't have to worry about this.

K so pressure palte huh?
Would it make sense that it gives me trouble only at High RPMs or when im really laying into it? Even if I just decide to smoke the tires a little bit in first, there will be almost no clutch left for 2nd....

What happens is at high RPM the centrifical force is so great that the diapram spring on the pressure plate & throw out bearing 'hang up'.
The result is the low pedal sensation felt when depressing the clutch pedal.
It is in a state where it tends to float if you will. An heavier clutch set will cure this.

hmmm.. Well good to know.. but sucks to know Ive spent $700 at the shop now getting the slave and master replaced, when neither of those werent the problem....

Im thinking LS7 Set up?

hmmm.. Well good to know.. but sucks to know Ive spent $700 at the shop now getting the slave and master replaced, when neither of those werent the problem....

Im thinking LS7 Set up?

Well, if you're replacing the clutch, it's a good idea to replace hydraulics anyways, so just think of it as parts you would have replaced anyways. Where you probably lost out money-wise was having it all done separately rather than at the same time as the clutch swap.

Regarding choices, what are your mods, driving/racing habits and plans, and what kind of tires do you run?

Car is stock, SLP lid is all...
Dont really plan on any mods.
The car is my daily driver, so I want a clutch thats easy to drive. I do run the car hard occasionally but nothing you wouldnt expect out of any other F-body.
Im running a 285 street tire