[OkDually]

Welcome to DieselPlace

 

[OkDually]

I will be replacing the fuel filter today and keep everyone updated

Make sure to check/replace the air filter also

 

[OkDually]

Replaced fuel filter, air filter.

Added diesel clean to the bowl, let it idle for 2 min and shut it off for 30 min

NO CHANGE.

I noticed it is worse once the engine is warm.
When I floor it WOT at 35mph, there's no power, it does accelerate but smokes terribly (black smoke).

It sounds like the same problem in this thread:

Stumped - 1993 6.5 surges at slight throttle

Well, I'm stumped! My 1993 6.5 diesel is surging only when the throttle is slightly pressed. I have no air intrusion and have 7-8 psi of fuel pressure at the engine. Recent work: New fuel line pre-lift pump (old had air intrusion) and installed a Reman IP a few months ago to try to resolve a...

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Not sure what to do next, I use this truck for my plumbing business and just thinking about selling it at this point.

Go through all of the grounds using the link provided in the 6.5L FAQ page. Grounds-Grounds-Grounds The importance of good grounds.....

Install a piece of clear line on the return side of the Injection pump Question: - 1999 GMC Bluebird 6.5L TD - PMD &amp...

 

[OkDually]

I will check the grounds and install the clear tube today.
The IP is hard to get to in the step van.
Is there anywhere I can install a fuel gauge on?

There are no issues at idle but it will smoke if I raise the RPMs.

The SES light is due to P0380 Glow/Plug Heater Circuit A because one of the connectors has corroded off. The truck still starts OK.

Seems like another one here with a similar issue. Asked him to update with his findings:

1998 6.5 surging / sensitive throttle - WITH VIDEOS

OK, I've searched the forum, and I'm a bit lost. I see lots of guys with parts bazookas just blasting parts at their trucks, and I've gotten alot of conflicting info. Ive got a 98 C3500 6.5. Bought it with 120k. At that time it had a goodwrench engine in it, unknown when replaced. Done...

www.dieselplace.com

You can T in a fuel gauge anywhere in between the lift pump and fuel filter housing

 

[OkDually]

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Unfortunately no change after cleaning the grounds.
There was no air bubbles in the clear tube.

I dont have a stalling issue.

In Park, I cannot gradually raise the RPMs, it just jump up to ~3k suddenly, then comes back down to normal idle. Today it idled rough after a couple high revs, I shut it off, restarted and it started idling fine.

I checked the solenoid and it plunges fine. Anything else I can check before I go after the IP and injectors?

Passenger side lines are corroded so I'll probably have to replace those as well.

Uncontrolled rpm's are two things...
1. PMD issue
2. armature in the IP is worn/bad = injection pump replacement

Since you have replaced the PMD that leaves only the IP..