Recently installed 350 blueprint 350tbi. This is the sending unit on the side of the Blick. Ecu reading correct with scan tool. Guage pegs. I have toned out the green wire. I have 11.8v at the cluster and 12.2 volts at the battery. I have tested the gauge in the vehicle and out by hooking straight to pos and neg on battery and straight from sending unit as well as grounding it out. I purchased another ac Delco gauge and another new sending unit car quest wt1049. When tested out side with pos, new and straight to sending unit, Guage slowly goes to pegged at 280. Does the same when installed and hooked up as soon as key is on. Please help. Don't know what else it could be unless I have purchased the wrong sending unit twice. Anyone one part number for sending unit that corresponds with stock temp guage?