← All symptoms
Symptoms
Misfire, rough idle, hesitation or surging
What causes it depends on the engine. 77 documented failures on 26 engines list this among their signs. Pick your engine for the causes ranked, how to tell them apart and the usual fix.
7.3 Power Stroke (1994.5-2003)
4 known causes, most widespread: CPS (camshaft position sensor) failure
6.0 Power Stroke (2003-2007)
8 known causes, most widespread: EGR cooler failure
6.4 Power Stroke (2008-2010)
2 known causes, most widespread: Piston ring failure #7/#8 (regen fuel wash)
6.7 Power Stroke (2011-present)
5 known causes, most widespread: Low-pressure fuel supply weakness (lift pump, filters, water-in-fuel)
3.0 Power Stroke (2018-2021)
1 known cause: CP4.2 high-pressure pump failure (contamination cascade)
5.9 Cummins (1994-2007)
2 known causes, most widespread: Common-rail injector wear / nozzle carbon (03-07)
6.7 Cummins 2007-2018
5 known causes, most widespread: Holset VGT turbo sticking / actuator failure
6.7 Cummins 2019+
1 known cause: Common-rail injector wear (2019+ 6.7)
Ram 1500 EcoDiesel (2014-2019)
1 known cause: Bosch CP4.2 high-pressure pump failure (recall 22V-406)
Duramax LB7-LMM (2001-2010)
2 known causes, most widespread: LB7 injector failures (the defining repair of the generation)
Duramax LML (2011-2016)
3 known causes, most widespread: Bosch CP4.2 high-pressure pump failure and fuel-system contamination
Duramax L5P (2017-present)
4 known causes, most widespread: EGR carbon buildup (valve and intake deposits)
3.2 Power Stroke (Transit)
1 known cause: Common-rail injectors / injection pump faults
ProMaster EcoDiesel (2014-2016)
2 known causes, most widespread: Glow plugs and module: cold starts
Sprinter 3.0 V6 (OM642)
4 known causes, most widespread: EGR valve and intake coking
Sprinter 2.1 (OM651)
3 known causes, most widespread: Glow plug module and cold starts
Triton (gas)
5 known causes, most widespread: Spark plug ejection / stripped plug threads (2V heads)
6.2 Boss (gas)
2 known causes, most widespread: Ignition service wear (16 plugs / coils)
7.3 Godzilla (gas)
3 known causes, most widespread: Cam lobe and lifter (tappet) wear, worst with long idling
3.5 EcoBoost (gas)
5 known causes, most widespread: Charge-air-cooler condensation: boost shudder / hesitation in humid weather
Transit V6 (gas)
1 known cause: Ignition service: plugs and COP coils
6.4 HEMI (gas)
3 known causes, most widespread: Lifter / cam wear (HEMI tick source #2)
ProMaster 3.6 (gas)
2 known causes, most widespread: 'Pentastar tick': rocker arms, hydraulic lash adjusters, cam damage
GM 6.0 / 8.1 Vortec (gas)
1 known cause: Ignition service at mileage: coils, wires, plugs (misfire under load)
GM 6.0 L96 (gas)
3 known causes, most widespread: Fuel delivery: pump, injectors, pressure (L96/LY6)
GM 6.6 L8T (gas)
4 known causes, most widespread: Direct-injection high-pressure fuel pump / injector failures
Built from the failure-mode records on this site: a failure is listed when its own symptom list describes this sign. Engines not shown have no documented failure with it in our records. How we tier and source facts.