The Nissan Path

Hi all, so with my father giving me his pathfinder. Which i love it came with the oil guage pinned on H. I did my research and got a brand new one from the nissan dealership. I put it in myself being careful not to tighten it so much. I drove around and no leaks but the guage is low when im stopped and perfectly in the middle when im driving. So i thought i should tighten it more since it wasnt nearly close to flush. So i did and it is still doing the same thing. Any answers would be much appreciated.

Thanks