so finally finish my swap and notice I have a slight knock. It only sounds like its coming from the drivers side behind the timing belt cover. thinking it my be valve clearance I went through and set all those. Didn't change, if i rev it over 2k it goes away. and it doesnt always do it. I pulled the plugs and they look perfect, aside from the noise it seems to be running great. Any advice? Anyone else have this problem? Im thinking maybe timing off one tooth but wouldnt it run like crap?

Timing belt tensioner may be weak, causing it to backlash. you can change this part without upsetting the tiing belt if you clip the belt to the pulleys before taking it off. 

 

Do you know the service history of the timing belt? 

pulled the covers, t belt tensioner is bad. thank you. dont know history I purchased it from a rolled forrester a year ago and just got it running in my wagonb last week. Looking at the price of the tensioner and belt I think i might as well get the whole kit with the water pump and everything and just do it all at once and call it a day

Go on Rockauto and get the Gates T-belt kit, if you do go that route 

Amazon had lowest price on the Gates kit last I heard.