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Chevrolet Silverado 2014-Present: Why is My Truck Idling Rough?

Chevy Silverado engines are known for being big but also smooth. Here's what you can do if yours is idling rough.

By Jerry Perez - June 26, 2015

This article applies to the Chevrolet Silverado 1500 (2014-present).

Big Chevy blocks produce a lot of horsepower and torque, and can definitely pull some weight. But albeit being strong, they are also known for their smooth revving and quiet running performance. Rough idling isn't only annoying, but it's more than just a vibration. It could be a sign of a component going bad, or another situation that may lead to bigger problems down the road. That's why we've compiled the most common reasons why your Chevy Silverado may be idling rough. Remember that while some of these are easy tale-tell signs, you may still need to visit a professional repair shop for further advice.

Step 1 – Clean MAF sensor

It could be getting a bad air reading.

When the engine is running but not causing any forward motion, everything about its behavior changes. Temperatures change the way the fluids inside the engine behave, and parts also do the opposite of what they are meant to do. Idling too much or too little can have a negative impact on your truck's performance. One of the first things to check when the engine is idling rough is to unplug the MAF sensor in the intake. The logic behind it is that engines lack air when they are idling because there is no stream of air going into the engine. If a MAF sensor is already weak, then it may provide a bad reading to the ECU and tweak the mixture rich or lean by error, which could cause rough idling.

  • Unplug MAF sensor and asses its condition.
  • Clean if it looks ok, or replace if it's been driven past its life cycle.
Figure 1. Silverado MAF sensor.

If the result of Step 1 yields no results, move on to Step 2.

Step 2 – Check the thermostat

It could be providing the wrong temperature.

The engine in the Silverado has an optimum working temperature, but until it reaches that temperature, its behavior and inner workings are working overtime. So in theory, if the thermostat is providing an erroneous reading to the engine, it could throw off its entire behavior, and the engine won't run smoothly until it thinks it has reached that operating temperature (which it may never reach if the thermostat is faulty).

  • Wait until the engine has completely cooled down.
  • Remove thermostat and check for corrosion or damage.
  • Clean old thermostat, or replace with new one.
Figure 2. Make sure your temp is settled in the middle of the gauge.

If the result of Step 2 still doesn't fix the rough idling, move on to Step 3.

Step 3 – Check the fuel filter

It could be dirty.

The fuel system begins with the gas tank, then the fuel pump sends it through the fuel lines, and finally it gets to the fuel filter. The filter cleans the impurities, which then finally arrives at the engine block. So if the fuel filter is dirty, clogged or malfunctioning, it could keep fuel from reaching the engine. The reason why the engine will idle rough is because it's not getting as much fuel as it needs to idle and maintain the necessary engine revs.

  • Locate the fuel filter along the frame of the truck (driver's side).
  • Remove filter from fuel lines.
  • Inspect it and replace if necessary.
Figure 3. Fuel filter.

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