I finally got around to cleaning out/checking my fuel injectors and the screens inside the injector openings were choked with rusty bits and what appeared to be rusty varnish.
The inside of the fuel rail was a mess too, even removing the fuel dampener revealed sandy rust accumulation _ I'm surprised in ran as well as it did.

I ended up using an industrial toilet bowl rust remover to dissolve the rust in the fuel rail, it was a mild solution if hydrochloric acid.
Given the truck did sit for 8 years with old fuel in it, I can understand a build up of old gasoline varnish, but the rust ?

I thought I was going to need all new injectors, but after carefully cleaning all the screens, it allowed the fuel to flow for proper atomization.
This is on my 99 Mazda B3000 rear wheel drive, standard.
I suspect that the plugged screens were not allowing the fuel to flow for proper cold start running.

I only took it for one drive, but that annoying micro surging when cold appears to be gone.

 

Gasoline contains ethanol, ethenol is hygroscopic (absorbs water). Leave gasoline to sit for long periods of time like that and you basically end up with a mix of rotten gas and water which can rust everything it touches. The insides of your fuel lines, fittings, regulator, rail, etc probably all have some degree of oxidation/rust damage.

 

I thought the fuel lines were stainless...?
At any rate, I could imagine what the old filter looked like, I know that's steel.
Just seems really odd, I didn't expect to see this sort of build up in the fuel rail because of the plastic tank.
The fuel rail itself seemed OK once I cleaned it _ the outside was a bit rusty through the chrome here and there, but was silver on the inside, just rust stained and lots of sediment.

I'll go under there with a magnet later and check the lines.

I also ran the pump for a 3 cycles and thankfully the fuel was clean that cam out.

 

Fords too cheap to use stainless. They are almost always regular steel with any number of different coatings over the years. (Also contrary to popular belief stainless steel also rusts to varying degrees based on the type) Also remember alot of other metal components are in the system, filler neck, fuel filter, parts on the pump, etc.

I wouldn't worry about it unless you see visible external corrosion anywhere in the system. Replace the fuel filter and run some seafoam and "heet" through the system to help clean up any other varnish and rust deposits, the heet will help remove any residual water in the system. then be prepared to change the fuel filter again if it's really bad.

 

Surprisingly the other end of things were in pretty good shape, the idiot mechanic who replaced the fuel pump just shoved the line on and it eventually blew off.
I removed the box (that was fun) to go over his work and properly install the line, so I inspected things then.
There was a new filter put in place when the pump was replaced.
You can imagine the state of the pump and old filter from sitting for 8 years with old gas in it.
I imagine the pump was pretty much seized.

It looked pretty clean, so that's why I was surprised to see the fuel rail in such a state.

There were small indications that there was something wrong _ slight hesitation and micro surging when the engine was cold.
Not bad enough to give a lean code though, but just enough from lack of fuel to suspect there was something wrong.
It idles better too because the spray pattern is nice and even now.

This is my first experience with a fuel injected vehicle, so I figured that the slight bit of movement of the engine was normal, it pretty much sits dead still now.
I could get an old carbureted engine with points to idle smoother.