Truck accelerates on its own? Here’s what to do

Truck accelerates on its own? Here’s what to do

Have you ever been in a situation where your truck accelerates on its own?

Scary isn’t it?

You’re not alone. This has happened to thousands of truck owners all over the world. It also goes by the name Sudden Unintended Acceleration or SUA.

Sudden Unintended Acceleration or SUA incidents have been reported for decades. There are several factors that contribute to this from driver error to automobile defects. The best thing to do when this happens is to remain calm & engage the emergency brake if the foot brake is unresponsive. Shift to Neutral and turn the engine off immediately. Make sure to report the incident to the manufacturer.

Reasons Why Trucks Accelerates On Its Own

There are many reasons leading to SUA. Here’s a list of possible factors with a brief overview and how best to respond to such situations.

Human Error

truck accelerates on its own after accidentally hitting gas pedal
truck accelerates on its own after accidentally hitting gas pedal

This is the most common reason why SUAs occur. Incorrect gear engagement, over/under estimation of distances from point A to point B are some mistakes drivers do. Pressing the gas pedal too hard or accidentally applying more gas instead of hitting the brakes, these are the other examples of human error in play.

This is the reason why thousands of SUA incidents are reported and ultimately dismissed. This has caused a huge discussion on whether the phenomenon is real or if people just want to put the blame on others or on the machine instead of themselves.

To avoid this, make sure you are totally familiar with the vehicle you are driving before getting behind the wheel. Practice transferring your foot from one pedal to another to ensure you have muscle memory in terms of their distance from one another. If you have depth perception, spatial recognition or difficulty estimating distances, you might want to have your eyes checked.

Before driving a new vehicle, you might want to do a few practice sessions before taking it on a long trip. This is the best way that you can familiarize yourself with the gear positioning, pedal distances and essentially how the car feels.

Unresponsive Pedals

This is a mechanical error that explains why your older truck accelerates on its own. Without proper maintenance, pedals can accumulate dust and grime over time causing it to become unresponsive. 

Another thing to look out for is rust. Oxidation between the metal surfaces can create irregularities leading to “sticking”. 

For instances like this, temporary solutions like spraying WD-40 on the affected areas can eradicate the problem. As soon as you can, clean the surfaces up thoroughly to avoid it from happening again.

Worn pedal springs causes the foot pad not to return to closed position, but remain in an open position even if you don’t intend to. This is extremely dangerous if you’re stuck in traffic and your car keeps revving even if you don’t want it to. 

Replace worn pedal springs immediately.

Cruise control issues

Older trucks that have this feature on might develop sudden unintended acceleration because of the mechanism allowing the cruise control to maintain a certain speed. Depressing the pedal and engaging cruise control with a faulty drive by wire can either open up your throttle in slight increments without you wanting it to do so or close it to the point where no fuel is delivered.

Have preventive maintenance done on your truck to avoid this from happening. 

Stuck throttle

Most instances where an older truck accelerates on its own can be attributed to a stuck throttle. Older trucks usually are carburetor type and the spring loaded mechanism is either worn, rusted or wound too tight leading to operational anomalies. This could either fully open your throttle giving you full speed from a starting position or keep closing off prompting you to apply more pressure than needed.

Stuck Throttle
Stuck Throttle

When stuck at fully open position, your engine will keep revving even if you don’t want it to and applying the brakes will ultimately fail as opposing forces within your vehicle take action.  

Have preventive maintenance done and replace the throttle mechanism immediately. You can also clean up the carburetor as excessive grime may be present leading to slipping or sticking.

Shorting of onboard electronics

As our vehicles becomes more and more advanced, malfunctions due to faulty on board computers and other advanced onboard electronics become inevitable. Damaged ECUs (Engine Control Unit) can produce the same effect as that of a stuck or faulty throttle on a carbureted system. 

Make sure you have your vehicle checked regularly if your older truck accelerates on its own and it comes equipped with an ECU or you had one installed as an aftermarket option. This will need the assistance of a capable expert who is certified to work with your specific ECU. 

Diesel Engine Runaway

This could be one of the reasons why your truck accelerates on its own. This happens when there is excessive pressure in the crank case forcing engine lubricant mist into the intake manifold. The lubricant burns just like diesel giving your engine an unexpected boost. This results in an uncontrollable surge forward or backward, depending on the gear or mode engaged.

Bring your vehicle in for an annual preventive maintenance to avoid this problem. This may include disassembling your engine to depressurize affected parts. 


Problematic Mats
Problematic Mats

Another common reason why SUAs occur and have been proven true which has resulted in a massive recall of Toyota trucks. Who knew that something as complex as a modern vehicle could be brought down easily by something as simple as a mat?

Sadly, this has been the case for Toyota who had to recall thousands of vehicles suffering from SUA. They found out that the mats would slip and go under the pedals preventing you from totally depressing it. Most people who experienced this just pressed their accelerator more firmly leading to an unintended surge in acceleration. 

By the time the vehicle had lurched forward at full speed, the person behind the wheel was unable to put on the brakes effectively because the mat also prevented it from being fully engaged.

This explained why most were unable to stop on time and their vehicles seemingly went on a rampage as it continued to move forward even if obstacles were already presented in front or behind it.

The simple solution to this was to put Velcro strips or use clips to keep the mats in place.

In conclusion, Sudden Unintended Acceleration can happen to anyone. If your brand new or older truck accelerates on its own, try checking if any of the symptoms above are present and make the necessary adjustments as soon as you can. Always remain vigilant and always take a new car for a test drive before taking it out on a trip.

Related Questions

What’s The Best Thing To Do When Your Truck Accelerates On Its Own?

Don’t panic. Apply the brakes or pull the emergency brake immediately. Place your gear in Neutral and shut off the engine. Report the case immediately to your manufacturer to have the incident documented and resolved. Take note of the cause of the SUA once you get your vehicle back.

Which vehicle brand has the most cases of SUA?

Based on recent reports, Toyota has the most reported incidents. This was followed by Lexus & Mitsubishi. This is still up for speculation as these recent reports were captured & made public immediately through social media. It is not known how many incidents have gone unreported in the past.

Are Trucks The Only Ones Affected By SUAs?

The answer might surprise you. No. This happens across the board from small cars to large semi-trucks. This usually happens to vehicles with automatic transmission but can also apply to manual transmission equipped vehicles. Remember to always be on guard to prevent it from happening to you.

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