To simplify the fuel system issues I would not be using the saddle tanks at all until I know for sure they are not full of crud.
I would be installing a new in cab tank with new fuel sender seals and body seal, and routing a new fuel line from new tank to fuel pump.
Bypass all the other tanks for the time being.
Change the fuel pump...buy an AC Delco one if you can find one...had lots of issues reported on Chinese built pumps from Autozone and others...actually look on the pump for country of origin labels...
Add a metal cased inline fuel filter after the pump...and enjoy driving your truck for a while...
When you are ready, you can then check out the saddle tanks etc...if you dont intend to do long haul runs in this truck, I would be removing the saddle tanks totally...
Standard tank holds 20 gallons...plenty of gas for normal runs and cruises.
You could also go crazy and install an aftermarket tank behind the rear axle and get rid of in cab tank totally...LMC has some suggestions in their parts manuals...usually something like a Blazer tank...choices abound...but I do like the KISS approach...Keep It Stupid Simple
