I'm pretty new to this myself, but will offer some insight based on my limited experience.
I know you say your connections are fine, but check them again. Usually jumping resistance is because of a bad connection to the + or - post, especially if you break the wire while tightening the screws.
If that's not the issue, check to make sure your coil is not coming into contact with other metal, i.e. the posts or well.
If that's not it either... Couldn't tell ya; that's the extent of my understanding from building micro coils in my igo w over the last few days.
Hope you work everything out.