I just went thru this prob, they ARE hard to find! A really good old school hardware store should have them. Mine was out of that size. Don't buy a HELP! or NAPA assortment, they don't go down that small. Finally found them in the boxes of assorted hardware at either Home Depot or Lowes. Can't remember which store, I think they are 3/32".
The last ones I found were sitting down in that pocket on the intake manifold hiding behind the bolt.:laugh: