wouldnt be the tensioner itself, as thats hydraulic.. it may be the pulley tho, check em all out.. wiggle em about and see if you have any play in the bearings.. will be hard, but you should be abled to give them a wiggle down the cam side.
if i was you id check shims myself, all you need is a set of feeler gauges you got some i'm sure matey. safer that way as you know, instead of going on a hunch
bgb has a step by step.
cold;
0.15mm - 0.25mm for intake side
0.20mm - 0.30mm for exhaust side