Do it yourself, change the spark plugs and wires on your GMC Sierra 5.3L V8, made between the years 2006 and 2013. You will require eight new spark plugs and wires and a spark plug wrench with an extension. This repair might take you more than 30 minutes.
First of all, we recommend you to open the hood of the car and unplug the negative cable from the battery. Next, you have to remove the plastic engine cover seen in the image below. You can do it very simply, by pulling it up with your hands.
After you do it, you should start removing the spark plug wires one by one, to get access to the spark plugs. In the picture below you can see how they should look. Just pull out by hand, the eight wires.
Now you have access to the spark plugs and you can replace all of them using the spark plug socket wrench. Because the access to some of the spark plugs is quite difficult, we recommend using a flexible extension to your wrench. After you remove and replace all the spark plugs, plug back the replacement wires. You can use some dielectric grease inserted on the wire’s extremity connected to the spark plug. At the end, reconnect the negative cable on the battery of your car and that’s it. These are the steps you need to follow in order to change the spark plugs and the ignition wires on your GMC Sierra, manufactured between the years 2006 and 2013.