Looking for a Mentor, pretty please with sprinkles on top

[Uncle Gump]

I know my 94 has a plastic tank... not sure why this one would be any different.

Being the fuel pump was replaced... I would start by looking at fuel pressure. If the fuel pressure is not within specs... then start looking at the tank/pump/regulator.

Does it have a nice stable idle? Or does it "hunt" up and down looking for a happy spot?

The "whistle"... is the intake ducting all in place? Did you take a good look at the vacuum hoses/caps. A vacuum leak can cause a whistle and an unstable idle.

Just a couple cheap checks before you just start ordering parts If you don't have a fuel pressure gauge... it is a reasonable investment if you plan on DIYing your auto repairs going forward.

 

[RuralRangerRoadin]

I know my 94 has a plastic tank... not sure why this one would be any different.

Being the fuel pump was replaced... I would start by looking at fuel pressure. If the fuel pressure is not within specs... then start looking at the tank/pump/regulator.

Does it have a nice stable idle? Or does it "hunt" up and down looking for a happy spot?

The "whistle"... is the intake ducting all in place? Did you take a good look at the vacuum hoses/caps. A vacuum leak can cause a whistle and an unstable idle.

Just a couple cheap checks before you just start ordering parts If you don't have a fuel pressure gauge... it is a reasonable investment if you plan on DIYing your auto repairs going forward.

I always DIY my auto repairs, and so I have learned as I have gone with whatever issues have come up I will definitely be looking into getting a fuel pressure guage, because even with the 94 aside, I slowly would like to start building my toolset to someday be able to have whatever tool I need for a given job.

I don't know how to check some of what you listed but I'm definitely going to look up everything and check it out, because that's been one of the most overwhelming aspects of the 94 is I can't plug my OBDII reader in and get even a small glimpse at what could be causing issues. I never realized how spoiled I was up until this point.

And it holds a steady idle for a bit (I'd say 10-15 minutes) before you can hear it start increasing and decreasing in rpms in a cyclical pattern. (almost reminds me of how a generator sounds when it starts running out of gas but not nearly as loud or dramatic.)

Excuse my inexperienced ways of describing some of this stuff

 

[rubydist]

Not all of the 90's era trucks had plastic fuel tanks, so his could be metal.

Its also possible that the "new" fuel pump the guy installed is not working right. Unfortunately, I have had infant failures on more stuff than should have, so the fuel pressure test is a good idea.

 

[Uncle Gump]

I was just stating to ensure the duct from the throttle body to air cleaner box was in place. Also... just a visual/touch feel inspection of all the vacuum hoses and vacuum caps.

The hunting idle when warmed up is a classic symptom of a vacuum leak.

 

[RuralRangerRoadin]

I was just stating to ensure the duct from the throttle body to air cleaner box was in place. Also... just a visual/touch feel inspection of all the vacuum hoses and vacuum caps.

The hunting idle when warmed up is a classic symptom of a vacuum leak.

Gotcha! 10-4 Thanks a million dude. I'm definitely gonna examine all the hoses, connections and caps today and check the duct work out.
I still have the opportunity to back out of the deal before I pay the other half of the amount and get the title, so I'm trying to see what all is possibly up with it and if it is worth it before I decide to finalize the purchase.
I appreciate the tips! I wouldn't have checked that and I don't think my dad or bro did whenever they looked the truck over.

 

[RuralRangerRoadin]

Also, just cranked it again right now to reassess, noticed there is a whirring/whining cyclical sound when the clutch isnt engaged, and the sound stops when you press down on the clutch. Only happens in neutral as far as I can tell with the truck currently parked in our shop area.