Clutch pedal vibration/pulsating

[NDISX15]

Should be ok then, tho I set all of ours around 2"......Not sure if the 1/2" would make that kind of difference. Shouldn't.

Have you dropped the inspection plate and looked at the pressure plate and springs while someone bars the motor over or bumps the key? Look for broken springs or anything out of place. Otherwise you're gonna be looking at the things that Rawze mentioned. Flywheel not machined/out of round, u joints/driveline out of whack, etc.