What makes a speedometer start bouncing?? Then when I start off from a complete stop the RPM got too

... be over 2 before my truck will shift and the speedometer kicks back on and still bouncing?? Also the abs like came on.. not both lights just the abs then when I kept driven it all the dashboard lights started flashing at me.. I have no What makes a speedometer start bouncing?? Then when I start off from a complete stop the RPM got too be over 2 before my truck will shift and the speedometer kicks back on and still bouncing?? Also the abs like came on.. not both lights just the abs then when I kept driven it all the dashboard lights started flashing at me.. I have no idea why.. I have a 2001 GMC Sonoma 4x4, 4.3 motor V6.. please give me some idea's on where I need too start???? idea why.. I have a 2001 GMC Sonoma 4x4, 4.3 motor V6.. please give me some idea's on where I need too start????