2000 2Wd,5spd manual. 3.0 FFE. My tachometer has been acting up for a while and now has stopped responding. Can someone please describe the signaling origination point? I know it is all electronic. I have taken my cluster out once before to change dash bulbs but I don't think this is a contact issue in the cluster. Where is the pickup on the engine? My Haynes schematic only indicates a feed into the ECM. What is the mechanical? Thanks.