I'm a new member but a long time reader. I'm having problems with my 9400 cylinder speed read out on my corner post. I'm combining corn and my cylinder rpm keep going up and down from 350 to 500 ( steady). I changed sensor,cleaned all connections. It must be electrical. It ready 350 rpm empty then when I start into the rows of corn it starts dancing up and down. Looking for different ideas to check out. Thanks.