Pre threaded holes in engine bay

I have several holes on the passenger side just behind the filter box that are pre threaded. They all look the same. I am considering mounting my viair compressor with those holes but can’t figure out the hole size and thread pitch/count. Anyone have an idea? I know they aren’t M8 and none of the other random bolts I have seems to work. Thanks!

 

Most are M8x1.25

 

Yeah it’s definite not an m8. I tried that. I think the second and third gens have m8 holes. These are a bit smaller.

 

If smaller then try M6x1.0 or 1.25

 

M6 sounds right but don't quote me. Pull a bolt from something nearby, it's probably the same size. Even with the right size fastener, you might need to chase the threads to clear crust and paint out of them before anything goes in smoothly.

 

I have my winch controller mounted where the ABS goes if equipped, I forget what I used for certain but it was just a standard M6 or M8.

 

Take a picture and point out which ones. Will be easier for us to crosscheck