shimano sti shifter problem
 

Hey guys

My rear shifter rattles - this is starting to drive me crazy, so I hope someone can help me.
It seems that the return spring isn't tight enough which means the lever is pretty loose (about 2mm of movement)and rattles easily. Is there any way I can adjust the spring's tension or do I have to keep riding on the hoods?

Thanks in advance!

Is it the return spring for the brake that you think is rattling, or the spring for the shifters? The way to tell is, does the lever rattle side to side or forward and backwards. And is it the small upshifting lever or the large brake/downshifting lever?