Your Cummins' injectors are worn out — normal around 250,000 km — and the marginal factory fuel supply helped wear them. We replace all six, the filter housing, and add a proper lift pump so the new set actually lasts. At your home.
The 6.7 Cummins is a long-haul engine, but its injectors are consumables on a roughly 250,000 km schedule. Each one fires multiple precision events per combustion cycle at extreme rail pressure, and over a quarter-million kilometres the nozzles erode, spray patterns degrade from atomized mist to crude streams, and internal seats begin leaking. Six injectors wearing at six slightly different rates is exactly the lumpy idle and uneven power you're feeling.
P0087 — fuel rail pressure too low — tells the supply side of the story. Worn injectors leak rail pressure away faster than the CP3 pump can comfortably replace it, and the deeper problem is that the factory in-tank supply setup feeds that CP3 marginally at the best of times. A starved CP3 cavitates and wears, leaking injectors drag pressure down further, and the whole high-pressure system slides downhill together. That's why the long cranks: rail pressure that bled off overnight has to be rebuilt from nothing every morning.
This is why the complete job is more than six injectors. The filter housing — a known weep point on high-kilometre trucks — gets replaced so the fuel path is sound, and a proper lift pump goes in so the CP3 is finally fed under positive pressure the way the system always should have been. Skip the lift pump and the cycle restarts: the same starvation that helped wear this injector set goes to work on the new one. Add it, and this repair is the last fuel-system job the truck needs for a very long time.
If your Ram is doing any of these, this is the likely cause:
Worn injectors are quietly expensive to ignore: they wash cylinder walls with unatomized fuel, dilute the engine oil, and in the worst case a badly dribbling injector can damage a piston. The supply-side starvation is grinding the CP3 down at the same time — wait long enough and the injector job grows a pump bill, and a failing CP3 can shed debris into the very injectors you'd just bought. At 250,000 km this is scheduled maintenance; at 300,000 km it's a gamble on the whole fuel system.
Yes — injectors, filter housing and lift pump are all driveway-serviceable with the right tools and discipline. It's a long day of work at your home, finished with rail-pressure verification and a loaded road test. No tow, no week-long shop visit.
Six precision injectors are genuinely expensive parts, and the labour to reach and correctly install them is many book hours — dealers bill both at full rate, and supply-side items get quoted as separate jobs. We price the complete package — injectors, housing, lift pump, filters — as one flat number you approve before we start.
Because the factory supply arrangement feeds the CP3 marginally, and that starvation is part of why your injectors wore when they did. A proper lift pump delivers fuel under positive pressure, protecting the pump and the new injector set. Without it, you're installing new parts into the same conditions that wore out the old ones — add the lift pump, or the job repeats itself down the road.
Mechanically yes, financially no. All six have the same kilometres, the access labour is the dominant cost, and the three you skip will have you paying that labour again within the year. One visit, the full set, supply side fixed — that's the version that's actually cheaper over any horizon past six months.
Send it over for a free second opinion. I'll tell you straight what the job actually involves — and if their quote is fair, I'll tell you that too.
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