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Running Rough / Misfire

Problems

Several things could be causing rough running or a misfire in your Caterpillar Semi

Cause: Stiction

Solution: Treat with Stiction Eliminator to clean out all of the injectors. Use Diesel Extreme to clean out the fuel system.

Cause: Mechanically failing injector(s)

Solution: If the truck continues to run roughly, investigate electrical issues and more serious injector issues.

Details

A condition of running rough can be one of many factors.

If the truck runs rough when it’s cold but clears up when the engine is warm, you have a stiction issue in your injectors. Treating with Stiction Eliminator will clear out all of the stiction gumming your injectors. We also recommend using Diesel Extreme to clean out the fuel system on your truck.

If the truck runs roughly only at idle, a stiction issue is likely, so treat this the same way.

If the truck is running rough all of the time, it can be a little more complicated. A severe case of stiction will cause a vehicle to spit and sputter consistently. This can be treated like any other stiction issue. These symptoms can also mean that there is an injector that has broken, beyond the point of our product cleaning it.

An electrical issue, such as a sensor failure (e.g., ICP sensor), can affect your truck in a similar way. You will need a scan tool to properly diagnose this.

The hardest to diagnose is an intermittent miss. It may be best to take the vehicle to a professional, depending on how good you are with your vehicles electrical system.

If you have any questions, feel free to contact one of our diesel experts.

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Running Rough / Misfire - Caterpillar Symptoms
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