Symptoms of a Bad or Failing Throttle Return Spring

Whether you drive a Kia or a 10,000 horse power Top Fuel Dragster, having a fully functional throttle return spring can save your life. On top of the throttle body of a fuel injected motor or carburetor is a butterfly valve, which opens when the accelerator pedal is pushed and the cable pulls it open. By opening this valve, you are allowing more air to pass into your engine. The butterfly valve then closes when you take your foot off the pedal. Involved in this process of closing the valve is the throttle return spring as it actually closes the valve. When it works properly, it helps to slow the vehicle down. When it's broken or wearing out, the throttle may stick wide open, causing a potentially dangerous situation.

The throttle return spring is attached to the throttle cable or it can be attached to the throttle body or carburetor. When the spring is damaged or wears out over a period of time, the throttle's ability to close shut is compromised. Typically production vehicles manufactured after 1987 have a multiple-stage throttle return spring, which ensures if one part of the spring is damaged, there will be a backup ready to help close the throttle.

Most of today's cars don't have issues with the throttle return springs, however, it is mechanical and can wear out over a period of time or due to added exposure to heat, oil, debris or other factors. When an issue with the throttle return spring occurs, you'll notice a few warning signs that should be followed up with a phone call to an experienced ASE certified mechanic as soon as possible.

Listed below are a few of the warning signs that a problem with a throttle return spring exists.

1. Engine RPM remains high after lifting off accelerator

As indicated above, the job of the throttle return springs is to "return" the throttle to a closed position. When the spring is damaged, the throttle body will remain open until either the pedal is manually drawn back by a driver's foot or gravity takes over and helps to close the throttle. However, when an engine is running, it creates a vacuum which wants to draw air into the intake, making it very difficult for the throttle blades to close on their own. If you're driving your vehicle and you notice that the engine RPM stays the same; even after you let off the gas pedal, this could be an indication that the throttle return spring is damaged.

If this happens while you are driving the first thing you don't want to do is panic. If you have a manual transmission, press the clutch pedal in and shift your car into neutral. This will allow you to come to a safe stop. If you have an automatic transmission, you can also shift into neutral gear and slowly apply pressure to the brake pedal. Once you come to a stop, try to turn the engine off. As soon as you stop, call a towing company and have your car brought home; as you don't want to drive the vehicle again until it is fully inspected by a professional mechanic.

2. Gas pedal feels spongy

Besides returning the throttle to the closed position, the throttle return spring also provides some strength to the throttle pedal. Most of today's modern cars are electronically controlled, so the pedal is very easy to activate and close. On older vehicles with the mechanical throttle linkage, the throttle return spring keeps the pedal solid and very easy to control. If the throttle pedal is spongy when you depress it, it could be caused by a broken throttle return spring or one that is wearing out.

3. Gas pedal doesn't return to normal position

Finally, if you release your foot from the accelerator and the pedal doesn’t return to the normal position, this is often a signal that the throttle return spring is damaged and needs to be replaced. A local ASE certified mechanic will know how to replace the throttle return spring on any vehicle as this is one of the first things taught in automotive class due to the serious nature of a mechanical failure with this device.

Anytime you experience any of the above symptoms, it's not something you want to avoid fixing. A throttle return spring is a very inexpensive part, and the cost to replace this unit is very affordable when you consider the price hikes associated to a vehicle accident. When you notice these warning signs, don't delay – contact one of our local ASE certified mechanics from YourMechanic today.


Next Step

Schedule Fuel System Inspection

The most popular service booked by readers of this article is Fuel System Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Fuel System Inspection reviews

Excellent Rating

(4)

Rating Summary
3
0
0
1
0
3
0
0
1
0

Michael

4 years of experience
120 reviews
Michael
4 years of experience
Volkswagen Jetta - Fuel System Inspection - Indianapolis, Indiana
professional ,informative and knowledgeable

Raymond

37 years of experience
236 reviews
Raymond
37 years of experience
Chevrolet Impala - Fuel System - Las Vegas, Nevada
Raymond was very knowledgeable mechanic and through in his testing. I trust him for any future from your mechanic.

Arturo

27 years of experience
238 reviews
Arturo
27 years of experience
Nissan Titan - Fuel System Inspection - La Mesa, California
Informative and efficient

Gustavo

17 years of experience
285 reviews
Gustavo
17 years of experience
Lexus IS250 - Alternator Repair - San Antonio, Texas
Gustavo did an excellent job installing my alternator. He was professional, pragmatic, and fairly priced. Thanks again.

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Replace a Throttle Controller
The throttle controller uses data to open and close the throttle. Common signs of failure include poor performance, stalling, and and rough idling.
B2106 OBD-II Trouble Code: Throttle Position Input Out of Range High
B2106 trouble code means there's a range issue with the throttle position input in a 4WD system, caused by a damaged circuit in the 4WD system.
How to Buy a Good Quality Throttle Body
Just Just like the throttle, the throttle body plays a very important part in how your fuel-injected engine runs, and makes the car move. The air intake system relies on the throttle body as a pivotal component. The air intake...

Related questions

Possible throttle issue

Hi there. The throttle body on your vehicle has a throttle plate that is opened by a cable which is attached the the throttle pedal in the vehicle. Over time, this cable can stretch. A longer cable requires further pedal...

how do you know if you need a whole throttle body compared to just cleaning it or replacing sensors

I would recommend cleaning and replacing the sensors first. Generally, throttle bodies do not need to be replaced completely, but rather just need specific parts related to them replaced. I would also recommend checking the mass air flow sensor to...

whats the best way to clean the throttlebody?

Hello. The best way to clean the throttle is to remove it from the vehicle. Find a throttle body or MAF cleaning product of your choice and use the nozzle that comes with it. When taking the steps to remove...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com