Aside from a worn out fuel pump, would these ground issues cause my pump to lose efficiency after driving at highway speeds for a few minutes?

 

To me, troubleshooting the primary circuit to the fuel pump relay, is easier and more logical than dropping a fuel tank and removing a fuel pump. Meantime, yeah, almost anything is a possible symptom of wiring/grounding issues but finding the cause takes testing with a volt meter.

 

Newly noticed issue...
my temp gauge along with fuel gauge aren't working...not needing help fixing those...BUT if the truck is overheating, would that cause my stuttering and stalling issue?..

 

Focus, lol. How did you get the 12 PSI fuel pressure reading in your earlier post? That, combined with the primary fuel pump circuit failure code, is why I would test the fuel pump relay primary circuit, with a volt meter. Also, I would check the grounds at the battery, engine block, frame, fender and radiator core support. By "check", I mean visually, as well as, if they look corroded, I would disassemble and clean them.

 

Honestly, I don't know which wires to test...or how to test the relay, tank switch, any of it...do I need to move the relay box to test wires under it?
All grounds look good.

 

Also, was able to run koer test and got a code 21, 25, and 52

 

I'm going to recommend that you find a mechanic you trust to troubleshoot the truck. One last question though, you mentioned a tank switch. Did the truck originally have two tanks? Go to a local mechanic with a good reputation. You'll be further ahead of the game.

 

Ok...fixed all koeo codes (got code 11). Fixed all koer codes...except ect code, broke sensor on removal...got the fitting out and am installing new one...any tricks to installing? It's a really tight fit.