[brucepick]

Synthetic will find leaks if there are some. Your call on whether you want to try it again. Synth will usually give you a tiny FE assist, I think mostly before fully warmed up when synth stays thin like it's supposed to.

The steps you took are good. If you go to same pump all the time that might help with consistency. Keep at this game and you'll see more progress. It doesn't come all at once

Upped tire pressure always helps. Don't be afraid to go to sidewall max, when tire is cold in am. Pump it up past your target when convenient during the day. Then check before leaving in am and bleed off some if needed.

For bigger gains I recommend some coasting. At first with engine idling. As traffic allows, accelerate to maybe 5 mph over your basic cruise speed. Put in neutral and coast. At 5 mph under the speed, go back in gear again and accelerate up again. Hopefully your cruise speed allows 5th gear. It's possible a truck will coast so badly, you will lose speed to fast to do much coasting. You just have to try it. I coast with engine off, but it takes some time to get the hang of that.

Another big area to work on is aero. Look at some truck threads in the Aerodynamics subforum. Pickup truck aero drag is usually pretty bad so I'm sure it hurts you even at 30 mph. Read some aero threads. Easiest fastest thing is a 2' to 4' plywood sheet across the back of the bed, by tailgate. Like a substitute tonneau cover. Cover it all if you can, but if you only cover the back portion it will help. Ford tested it and recommend it. Keep the tailgate up.

The good news is, it's pretty easy to work on the bed and on the underside too. You'll also find aero threads on front air dams. Lots of pickup truck modders use one, and pretty easy to make.

Good luck!