I have a 99 blazer 4.3 4wd 2 door 5 speed Some days my clutch is great but other times after driving on the highway the clutch will start grabbing right off the floor If I tap the top of the clutch pedal it would go back to normal but now it just grabs as soon as the clutch comes off the floor has anyone experienced this issue?

 

when is the last time you bled the master cylinder?
remember you need to get the cylinder up high, so all the air is out

 

Had a grabby clutch like yours, but being a good old clutch-man I just babied it, didn't see any leakage or hear any noise. Last weekend the clutch refused to disengage, had the Blazer towed to the shop, it's still there, awaiting new clutch kit and flywheel as a result of leaking slave cylinder and worn-out disk.