When I shift from 3rd to 4th at redline and hit 4th, it STICKS at 6000 RPM even though I have my foot all the way down and the car doesn't accelerate.
Is my clutch slipping?

But when I'm in 4th at 3000 RPM and floor it, it redlines easily and the RPMS don't "Stick" at 6000.

I was running 10 PSI btw

 

Your engine should still rev if your clutch is slipping.

To see if your clutch is slipping: go about 5-10 mph in first, then shift into 5th and floor it, if the car bogs your clutch is fine, if it revs then your clutch is slipping.

 

not really. If it is just starting to slip, it'll hold at a certain rpm during a hard sift because it is trying to catch, but doesn't fully catch nor fully release. When it slips so much it goes to redline, you're SOL and need to call a truck.

-C