Ford F-150/F-250: Why Does My Truck Shake?

Here is a guide to troubleshoot a shaking Ford F-150 or F-250 Super Duty.

By Tom Cavanagh - November 11, 2014

This article applies to the Ford F-150 (2004-2014) and F-250 Super Duty (2005-2014).

You've had your wheels balanced and your alignment checked, but your truck still vibrates as you drive down the road. The problem could be under your hood. Just as a runner needs oxygen to perform properly, so does your engine. There are a number of things that can happen to the delivery of fuel, its ignition, and the mixture of gasses and air in the combustion chamber that can cause your engine to vibrate and shake your truck. Here are a few simple things you can do to stop the problem.

Step 1 - Check the spark plugs

One or more of them may be misfiring. You are looking for worn or broken firing tips on the plug. If you use a diagnostic tool, it will tell you which plug is misfiring.

  • When the engine is cool, gently pull the red locking tab on the spark plug power plug up to unlock the release.
  • Press down on the black release tab and slide the power plug straight off of the ignition coil.
  • Remove the single bolt holding the ignition coil in place and pull the ignition coil up and out.
  • Use compressed air to blow out any dirt or debris that may be sitting on top of the exposed plug. You don't want it falling off the plug and into your engine when you remove it. That would be a very bad thing.
  • Using a 5/8 spark plug socket with the 6 inch extension and 3/8 drive wrench, loosen the spark plug by turning it counterclockwise.
  • Check the spark plug, place it back in or replace if needed.
  • Figure 1. Check the spark plugs for wear and breakage.
  • Repeat as necessary.
  • Reverse the process to replace the plug.

If the vibration does not go away, go to Step 2.

Step 2 - Check or replace the fuel injectors

Clogged or dirty fuel injectors cut the performance of your engine. Before you check them, depressurize the fuel system and disconnect the battery.

  • Use the cut-off switch to depressurize the fuel system if you have it on the passenger side front foot panel. Simply remove the plug in the picture below.
Figure 2. Remove the plug to depressurize the fuel system.
  • Remove the electronic plug from each injector. Lift the end of the fuel rail nearest the front bumper and pop each injector free (Figure 3).
  • Check your injectors. Look for clogging from dirt, old fuel, and carbon build-up (Figure 4).
  • Figure 3. Check the fuel injectors.
  • Figure 4. Replace if needed.
  • If you need to replace any, make sure you lubricate the O-rings on the new ones with engine oil and place it on the end of each injector.
  • Insert all new injectors into the engine hole; push downwards until they are seated properly.
  • Reverse the removal steps and reconnect the battery.
  • Start the vehicle to confirm installation.

If this does not solve the problem, move to Step 3.

Step 3 - Check for vacuum leaks

  • Spray soapy water on various hoses where you think the leak might be happening.
  • If you see bubbles, you have found the leak.
  • Change any leaking hoses.

If you don’t find any leaks, proceed to Step 4.

Step 4 -Check the EGR valve

The Exhaust Gas Recirculation valve (EGR) sends combustion gases back into the combustion chamber for cleaner emissions and better performance. Note: the engine has to be running to proceed with this step, so be very careful!

  • Remove the vacuum hose from the EGR valve.
Figure 5. The EGR valve.
  • Ask an assistant to pump the gas pedal.
  • Once the engine starts idling, apply vacuum with a vacuum pump.
Figure 6. Use a vacuum pump.
  • As you apply vacuum, the engine should idle roughly. It may even stall.
  • Apply vacuum again, and hold the vacuum for 20 seconds.
  • The vacuum pump gauge's needle should stay steady.
Figure 7. Watch the needle.
  • If the needle doesn’t stay steady, check that the vacuum hose is connecting the vacuum pump to the EGR valve and is making a tight connection on both the EGR valve and vacuum pump.

Figure 8. EGR valve.

If the engine idle grew worse when you applied vacuum with the vacuum pump, and the vacuum pump’s gauge needle stayed steady, then this result indicates that your EGR valve is working properly.

Featured Video: Why Does My Truck Shake?

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