Dodge Ram 2009-Present: Why is My Truck Running Rough?

This article applies to the 4th generation Dodge Ram 1500 (2009-2015).

The fourth generation Dodge Ram has received rave reviews, and not only for its aesthetics, but for its proven engine performance. Today's trucks are getting better fuel economy and producing fewer emissions, all with increased horsepower and torque numbers. In the case of the Hemi equipped Ram 1500, Chrysler has been using a "Multi-Displacement System" that allows for half of the engine's cylinders to be shut off at cruising speeds, or while the throttle is closed. A subtle difference can be felt by the seat of the pants when this system activates and has caused owners to worry that something is wrong with their truck. This system is typically not very intrusive. However, if you are experiencing a severely rough running engine often accompanied by cylinder misfires, it is likely an entirely separate issue. Fortunately, problems associated with a rough engine are usually easily fixed and often require little to no money to get the truck operating normally. This article will outline some of the issues associated with a rough running engine in the Dodge Ram 1500.

Step 1 – Poor fuel quality

You could have dirty fuel in your gas tank.

Many owners have experienced rough idling and/or cylinder misfire issues on their Ram trucks and have been baffled as to what the potential issue may be. Multiple trips to the dealership and the replacement of various components did not eliminate the issues and left owners scratching their heads. Additionally, many individuals have reported that the technician at the dealership has recommended a better quality fuel, as poor fuel can cause engine misfires and even clog up fuel injectors. Owners have reported that a switch to a different brand and higher octane fuel has eliminated their rough running issues. It is also not a bad idea to occasionally run a bottle of fuel injector cleaner through the engine to reduce the chances of buildup in the injectors that occurs from modern fuels containing ethanol. In any case, using a different fuel can be a cheap, effective way of improving engine performance.

If you're already putting in higher quality fuel and your injectors are clean, then go to Step 2.

Step 2 – Throttle body

You could have a dirty or faulty throttle body.

The throttle body has a major effect on engine performance, as it controls the amount of air entering the engine. Unfortunately, excessive carbon buildup on the throttle body is a known issue on the Ram 1500 and can cause rough idling as well as poor engine running conditions. Since the throttle body is a fly-by-wire system, the PCM controls minimal throttle opening while at idle, and if contaminated by carbon buildup, it can highly affect airflow. The result is often an engine that will stumble, shutter, and feel like a cylinder misfire occurring while at idle. The cause of this has been linked to the PCV system placing crankcase vapors into the intake manifold just behind the throttle body. Oil vapors and moisture will cause carbon buildup on the backside of the throttle body and butterfly valve. Regular cleaning of the throttle body (or the installation of a catch can) will reduce the likelihood of engine issues caused by carbon buildup.

(Related Article: Why Am I Experiencing Carbon Buildup? - DodgeForum.com)

If the throttle body is clean, proceed to Step 3.

Step 3 – Spark plugs and coils

The problem could be a combustion issue.

The spark plugs are responsible for igniting the air-fuel mixture in the cylinders, and the coil packs provide the necessary voltage to fire the spark plugs. Spark plugs are wear items that should be replaced at regular maintenance intervals. Over time, the electrode on the spark plugs will begin to erode and create larger gaps for the voltage to jump across. These extended gaps can strain the ignition system, as it requires more voltage to produce the same amount of spark. If left long enough, the individual ignition coil packs can become damaged and result in cylinder misfires. Dodge recommends a 30,000 mile spark plug replacement interval for their Hemi equipped Ram. Installing a new set of spark plugs can be an inexpensive fix to your rough running condition. If the problems persist or you are getting a check engine light that indicates a cylinder misfire, look into replacing the coil packs, which are relatively cheap at approximately $30 per coil pack.

If the spark plugs and coil packs are all firing correctly, soldier on to Step 4.

Step 4 – Powertrain control module

The issue could be stemming from the vehicle's brain.

The Powertrain Control Module (PCM) is the brain of the truck; it uses signals from various sensors to allow for proper engine operation. The PCM controls things such as fuel trims, ignition timing, multi-displacement system operation, etc. Like your home computer, the truck's PCM can experience a bug that can affect certain parameters, or illuminate a check engine light and cause a rough running condition. A simple reboot of the PCM has helped many owners clear their check engine lights and restore proper engine operation. Similarly, Dodge has released a technical service bulletin that relates to flashing the PCM with new and improved software to improve engine performance. A quick call to your local dealership can inform you if your truck is in the affected range that needs a new flash.

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