Strange issue

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Jul 29, 2018 | 11:21 AM

jazz77

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From: North Dakota

Strange issue

First of all let me preface this by saying I am not a diesel guy or much of a mechanic. I do all of the basics for my own vehicles: oil changes, brakes, plugs etc. I am capable of the occasional more advanced project thanks to YouTube .

So I have a '01 Excursion with the 7.3 that has been having some issues. The truck will lose power and have a very rough idle. I know at least part of the problem was vacuum leak from the hubs being replaced with manual ones. Yesterday I noticed that it seems to do it when the vehicle was angled down towards the front. I've also noticed that venting the coolant overflow seems to help.

Any suggestions are appreciated.

Jul 29, 2018 | 11:38 AM

Colorado350

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From: Colorado Springs

How much fuel in the tank, less than 1/4 of a tank? Google Hutch/Harpoon mod. The pick up foot breaks off and it can’t pick up fuel.

Jul 29, 2018 | 11:40 AM

Firefighter 1406

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From: Northern Indiana

Preference as I am no expert either. I am just getting back into driving my 7.3 again so I am a little rusty. But just thinking out loud. Any white smoke associated with the rough idle? If relieving the pressure off the coolant overflow helps make me think coolant is getting in the cylinder through the injector cups and burning causing a rough idle? How does your oil look? Does the coolant in the overflow have a sheen to it? Smell diesel in it?

Colorado has a good point too ⬆️

Jul 29, 2018 | 11:58 AM

jazz77

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From: North Dakota

It's done it at times where there was at least half a tank in. No diesel in the coolant and the oil was normal when I changed it two days ago

Jul 29, 2018 | 12:20 PM

Walleye Hunter

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From: Douglassville, PA

The vacuum system is an electric pump and is only used for the hubs and HVAC system, there is zero chance that it has anything to do with your rough running issue. fuel tank pickup would be one of the first places I would check. Try keeping the truck over half full of fuel for a while and see if it changes. Is your oil level full? Oil pressure is necessary for your injector system to function.

Jul 29, 2018 | 12:57 PM

jazz77

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From: North Dakota

The oil is good as I just changed it. Yesterday the truck ran fine except the 2 times I parked at a slight decline. It ran rough until I was on even ground