As the title states I can't get my intercooler clamps tight. Even fully bottomed out the intercooler slides around. It is so loose that I can slide the coupler off of the intake manifold side. Is this common? How do I fix this?

 

Are you using stock intercooler, stock boots and clamps? Are you using the right clamps on the right sides?

 

Sounds like you need either new IC Boots, Couplers or both.

The Boots actually expand some when engine is under load so like a used balloon, they expand easier over time absorbing some of the pressure and providing a bad seal.

I had similar issue when they were 8 yrs old and purchased new couplers and rubber boots. Problem solved. Tried the aftermarket ones, they cracked or didn't fit well so back to OEM.

Would also consider cleaning out the inside of the IC by spraying some CRC brake clean non residue formula thru it. Let the inside air dry while it is standing on end or put some air pressure thru it to help it along. Wipe it down and button it all back up with new hardware.

 

Bet the clamps were overtightened and are stripped...
Get new ones.
+1 on getting new boots...they get brittle and stiff with age...if ones splits...you can get stuck.

 

I had the same issue. I took a file to the "pin" side clamp, the one that goes into the other, and removed(filed) away some length. Prevents bottoming out of the clamps. Worked for me, good luck.