Did this ever get solved. Curious to know what the fix was.
ran into the same when transferring an h swap from 99 to 01. my fix was to run an aftermarket guage and sending unit.
Yep, see SergA'a post above. You'll need a 98 or 99 gauge cluster. Run a single wire from the single connector sending unit on the side of the head (under the distributor) to the C2 connector on the gauge cluster.
Connects to this wire - C2 (Yellow/Grn Stripe)