thats very niceThere is a clear urethane topcoat on the parts. Don't know much about the process but it takes a lot of water. Iv'e seen people use this for exterior trim on cars and even engine parts so it must be pretty durable.
Make sure the units are psig. psia or kpa would be confusing. A side by side with an analog gage might be helpful.85psi at idle? That's concerning.
A couple things. Fuel senders, I've gone through hell trying to find a sender that works with Dakota Digital (and it seems both of your problems are things that DD have trouble with). I'll dig up the instructions - IIRC the Ford senders work opposite the GM sender (don't quote me, let me find that paperwork).I just picked up a test gauge. Probably get that done tomorrow.
Also try a new temp sender.