Maybe you can try to slow it down for him...like begin at placing a treat on the floor in FRONT of him and point to it and tell him whatever you normally say for him to "go get it". Then move it off to his side, hear his paw...tell him to "go get it". Then again put it further still toward his hide quarters (hopefully the whole time he'll be in a sit or a down), and continue this process till it's behind him. Perhaps he just needs to see that he needs to look for it and learn to sniff it as confirmation of having found it. I had to teach one of my dogs to do that in the past...he wasn't much into using his nose, he was all EYES lol. Hope I have helped a little.
