What causes the speedo to act up all of a sudden? If I pull out and stay under say, 25mph, it stays on zero......once it comes off zero, it reads way high and will eventually go past 100 and stay there even if I slow down. I also have the vibrating fuel guage needle "hummingbird needle" and the oil pressure is all ratchety. Im assuming the oil pressure is a sending unit??? Is the speedo problem a Vehicle Speed Sensor??