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My 1993 has always had this surge or fishbiting that usually occurs at about 1800-ish RPM, usually in all of the gears, but certainly in 3/4/5. It feels like the fuel is getting cut off for a split second and then reapplied. I originally thought it was a failing injector so I recently replaced all 8. New Bosh injectors - all work great and the idle is smooth as butter. The fishbite went away for a bit but has returned just like before. 馃槱 I have no visible fuel leaks and my fuel pressure gauge never does anything strange. Fuel PSI at idle is 7 on a cold start, 5 at temp, and never bounces around when driving.

Recent new parts over the last 6 months include: AC Delco OPS, AC Delco Lift Pump, Diamond Eye 4 inch exhaust, S&B Cold Air Intake with snorkel delete, GlowShift 3 in 1 EGT, Boost, Fuel PSI gauge, 8 NEW Bosch Injectors, oil & fuel filters of course.

Where else should I be looking? Have I missed something?
 

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My 1993 has always had this surge or fishbiting that usually occurs at about 1800-ish RPM, usually in all of the gears, but certainly in 3/4/5. It feels like the fuel is getting cut off for a split second and then reapplied. I originally thought it was a failing injector so I recently replaced all 8. New Bosh injectors - all work great and the idle is smooth as butter. The fishbite went away for a bit but has returned just like before. 馃槱 I have no visible fuel leaks and my fuel pressure gauge never does anything strange. Fuel PSI at idle is 7 on a cold start, 5 at temp, and never bounces around when driving.

Recent new parts over the last 6 months include: AC Delco OPS, AC Delco Lift Pump, Diamond Eye 4 inch exhaust, S&B Cold Air Intake with snorkel delete, GlowShift 3 in 1 EGT, Boost, Fuel PSI gauge, 8 NEW Bosch Injectors, oil & fuel filters of course.

Where else should I be looking? Have I missed something?
Start by installing a piece of clear fuel line on the return side of the Injection pump ( as shown here):
If you notice any air bubbles in the line then you have an air intrusion and need to hunt the source of the leak.

Open your fuel cap. if you hear a large "Whoosh" sound then you have a restriction and need to modify your cap for better venting.
Have you changed your fuel filter? If not, then replace it.
 
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Discussion Starter #4
Thanks OKDually and DieselPro!

I'll be looking into these over the next few days. I had a water line burst under the house last night. Thankfully we got it fixed by this afternoon.

I got some clear fuel line this evening and will get that set up probably tomorrow. Also, I get no "woosh" at the fuel tank when opening the cap. If nothing else, I will investigate the fuel tank sock. I have to pull the bed to repair some rust spots - and it will also give me a perfect opportunity to set up a gooseneck hitch.
 

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Discussion Starter #5
Update:

Finally installed clear fuel line on top of the IP. I can see very tiny bubbles traveling through the line. Upon looking over everything, nothing really seems suspect except for this fitting next to where I installed the line. There is the possibility that I made a small m mess when removing the old hose, so I will let everything dry and examine again. Pictures are down below.

Also, I am working on a pre-lift pump filter set-up for when I eventually remove the fuel tank sock. Big thanks to Leroy Diesel for the fittings!
634870

634871
 
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