[Klas]

Thanks for the responses so far.
I'm sure I have the correct sender and used no sealant installing it.
Talked with the Truck Shop where I bought the gauge. They suggested checking an adequate ground at the gauge to the cluster, and the cluster to the dash. Also, check that the two posts on the gauge are sufficiently isolated from the housing.
They said they've had good luck with these gauges and want to know what I find. Further offered to replace and test my gauge for proper operation.
Will check today and update.