When blipping the throttle on my 5MT at idle when motor is fully up to temp., I get what can best be described as valve slap or knock. Doesn't happen when smoothly giving throttle, only when blipping. Also happens when blipping during a downshift, say from 3rd to 2nd. Sounds like loose timing chain tensioners or valves out of adjustment. Also, valve train sounds a bit like a diesel motor when idling. Has anyone experienced that knock from blipping or the diesel like valve noises when idling? Dealership and SOA have indicated that its normal, but I have had an independent Subaru shop tell me that its definitely not normal and sounds like valve train out of adjustment. Help or thoughts anyone?