I had the timing chain, cam chains, tensioners, guides and water pump replaced on my 06 X with a little over 121k miles. On my way home after picking it up, I noticed the oil pressure gauge on my gauge cluster operating a little weird once the vehicle was warmed up (about 15 minutes of driving). I have one of the Xterra's with the live gauge. There is a video post on this forum showing the exact problem I'm having. I'll post a link to it at the bottom. When I am driving, even at low speeds, the gauge would sit steady right around the middle where the oil can is. If I accelerated hard, the needle would raise as oil pressure increased. When I would come to a stop and idle, the needle would drop slightly then jump around. The needle would move from the line to the right of the low line on the gauge up to the middle where the oil can is and jump everywhere in-between. This is new behavior. About 5 months ago I had the sender fail and my oil pressure gauge was pinned high. It was replaced with a Nissan sender. So far, the shop removed the sender to check if any debris got in it and changed the oil. That didn't work. They replaced the sender with another Nissan sender and changed the oil again. That didn't work either. They hooked up a mechanical gauge and tested the oil pressure. Everything checked out okay. My gauge still jumps around after about 15 minutes of driving. I've read that one person had to hook up a mechanical gauge and drive with the mechanical gauge in the vehicle to record oil pressure jumping around. I don't notice any unusual sounds coming from the engine. No knocking or loss of power either. The low oil pressure light and check have not come on. I've read about the oil gallery/galley gaskets blowing out on the Z cars and Infinities with the 3.5L and 3.7L but my local Nissan dealer has never heard of this happening to the VQ40DE engine. I've only read about this happening to the Frontiers and Xterra's on forums like this. If the mechanical gauge reads okay, could those gaskets be the problem? Here is the video:If you read the comments below the video, most people are responding with oil gallery/galley gaskets needing to be replaced.