I finally got this gauge installed a few weeks ago and got all the leaks out of the line and everything, but recently the needle's been jumpin around a lot. starting up from low idle it will just jump from like 10psi to 20, and so on instead of moving evenly, and usually if I'm drivin on the highway or something and its up near 80psi, when I let the engine wind back down to idle, the needle starts back towards 10psi, and then jumps way past 100 and just peaks for a few seconds, then drops to the normal position. anyone know why this is? bad ground maybe?