more knock problems

[royston1xx]

Every time i hit 5400rpm or higher at any load (half throttle boost and no boost) it hesitates and the knock goes to 100 plus so i back off,this has only started happening all of a sudden as no changes have been made to the car that would effect it.It always starts to flash at 5400rpm though no matter what im driving like,any suggestions would be great,thanks Roy.

Mods on car are-intake
downpipe
midpipe
blitz catback
mild port
frount mount
1200cc sec injectors
cosmo 20b pump
The only thing i can think of is maybe the 1200cc inj are not working correctly.