Engine cough and excessive knock

[mikaelrules]

Hey guys, my problem started out when an intercooler hose popped off and the car was limited to 3000rpm. After getting the hose replaced, the car seemed to run fine for a few days. Then just a while ago, while at about 4000rpm, the engine coughed twice. From that point onwards, whenever I hit full boost, the PowerFC starts reading excessively high knock levels, to the point of the check engine light starting to blink.

My first guess are the spark plugs. Can bad spark plugs cause excessive knock readings? The car runs totally fine when off-boost.

Btw, I'm running an SR20DET with a PowerFC and T28BB turbo.

Any help would be appreciated. THanks!