Need some help or advice! 6.0 with cylinder 1 issues.

Need some advice/help:
First off let me say I hate asking for help. HaHa. We are usually good at fixing things without issue but I have one that is just killing me.
2004 F-250 6.0 with high miles(250k).
Back story: Good friend of mine bought the truck with a bad motor. Motor was rebuilt, studded, ******d, "bulletproofed" with all OEM parts and gaskets. Truck was tuned at that time as well. This was about 20,000 miles ago.
Truck always had a VERY intermittent but minor skip to it and would throw a cylinder 1 contribution code. Problem would show up after a hard pull after coasting down to a light.
Now about 5-6 weeks ago the truck essentially died on the road while out plowing. He towed it down, checked filters. Failed injector on the right bank leaking compression into the fuel system. Replaced all injectors(OEM) on that bank. Truck ran fine, buddy took it back. 2-3 weeks ago it had that skip issue again but this time is was like a completely dead hole. Cylinder contribution test showed cylinder 1 again. Buzz test while it was acting up finally showed a circuit error on cylinder 1 as well. I personally checked it out this time and saw an issue with the connector. 2 pins were pulling back whenever the harness would move. Rather than dick with anything I ordered a new harness and installed. Thought we figured out our issue from day 1 with it and all would be well.
Of course not though, can never be that lucky. Problem came back. No more circuit code though. If you drive it enough the contribution code does return.
So we had a good FICM here and I swapped that in with no change.
Finally did something we should have done a long time ago and checked fuel pressure. It was low, dropping down to 30-35PSI at times. Replaced the pump and now have over 50-55PSI. Problem is still present of course. I can almost make it act up every time I drive it now by warming it up and doing a hard pull on the highway. Coast down the off ramp and when it gets down to idle it will have a dead hole and run like ****. Once the RPMs come up it clears itself out.
We are at a loss and my next move is going to be seeing if my dealer will warranty the injectors for me and go from there.
FICM voltage is good. ICP is good. I do think I have seen a P2288(ICP too high) code before when scanning it once.
Everything we've replaced has been for obvious reason(failure) but anything I do from here I feel like I'm throwing parts at it which is not what I want to do.

TL;DR: Issue with cylinder 1 skip after hard pull. Rebuilt motor. New injectors on that bank(leaking compression). Replaced FICM. Replaced injector harness(bad connector). Replaced fuel pump(low PSI).

Thanks in advance for any insight/help.

I'd definitely try another injector first.


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Have you checke fuel pressure while the concern is happening? Also, have you checked oil level/quality? Is it possible it is fuel diluted and causing aeration?

I would disconnect the ICP and see how it runs. The sensor or connector sounds flakey with that P2288 code.

There may be other things (ie damage done when you did have low fuel pressure), but I would start w/ the ICP disconnect.

Also interested in the bubble test results and if you have any fuel dilution as mentioned above!

Replacing that injector now. I'll report back with how it runs after. I have to say, confidence level is not high. This truck has been very aggravating.

I was getting icp codes and a couple cylinder codes and truck would die similar to the problem you have. I eventually replaced the entire wire harness not a problem sence.

Kedstrokin said:

I was getting icp codes and a couple cylinder codes and truck would die similar to the problem you have. I eventually replaced the entire wire harness not a problem sence.

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Good advice, that would have been wise to investigate (ie disconnect the ICP sensor as a test).

I finally drove it with a fuel pressure gauge attached and pressure is dropping a lot under heavy load to WOT. I saw as low as 25PSI before getting out of it. It was a pretty quick drop as well. The truck didn't act up on my drive but I would just about guarantee if I continued driving it that it would. My next move is going to be dropping the tank and taking a peak inside. The fuel level gauge doesn't work anyways so it's not a totally lost project. My next place to look would be the assembly in the frame rail.

Pressure below 45 psig will damage injectors. Most of the time (but not all), low fuel pressure is a regulator issue, not a pump issue.

6.0Powerjoke said:

I finally drove it with a fuel pressure gauge attached and pressure is dropping a lot under heavy load to WOT. I saw as low as 25PSI before getting out of it. It was a pretty quick drop as well. The truck didn't act up on my drive but I would just about guarantee if I continued driving it that it would. My next move is going to be dropping the tank and taking a peak inside. The fuel level gauge doesn't work anyways so it's not a totally lost project. My next place to look would be the assembly in the frame rail.

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Had quite a few that the sock rots off and half ass plugs the pickup. Since you put a new pump in it, i highly doubt thats your issue. It could be the regulator though too, as stated.

bismic said:

Pressure below 45 psig will damage injectors. Most of the time (but not all), low fuel pressure is a regulator issue, not a pump issue.

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It did get a blue spring kit when the truck went together, that's not to say something couldn't have gone bad with it.

6.0 Tech said:

Had quite a few that the sock rots off and half ass plugs the pickup. Since you put a new pump in it, i highly doubt thats your issue. It could be the regulator though too, as stated.

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It's on the lift now so we can drop the tank. That was my thought and why we are dropping it.

Thatll do it... glad ya found it!

Thanks. I am too. New strainer will be here this morning and then I hope this thing purrs like a kitten. LoL