2009 Hyundai Sonata surges at takeoff and acceleration

40

Asked by Mar 20, 2017 at 01:47 AM about the 2009 Hyundai Sonata GLS

Question type: Maintenance & Repair

I have a 2009 Hyundai Sonata which has been a great car, having had only one problem with the starter in the seven years that I've owned it. But now, there seems to be a 'lag' in the throttle in takeoff from a stop or when decelerating then reaccelerating.

At a stop, if I press on the pedal slowly, there is no response until I continue to press on it slightly father. When it finally starts to accelerate, it does so with a sudden jerk or surge. What would cause this? I thought maybe the throttle cable, but more knowledgeable people than I told me that it has an electronic throttle body and no accelerator 'cable' per se.

Someone suggested the possibility of carbon deposits on the throttle plate, but I removed the air cleaner cover and boot and from what I can see inside the throttle body, there does not appear to be any deposits on the throttle plate. A little discoloration around the top and bottom edges of the plate, but nothing that I would call carbon deposits.

I've been told not to try to open the throttle plate by hand... To turn the car's ignition to the run position and have someone depress the gas pedal until the throttle plate opens. I tried this, but the plate does not move unless I actually start the car.

I'm not even sure this is the problem. I really don't see anything that I would consider a build-up on the throttle plate. It's a difficult place to see and even harder to reach in to. Does anyone have any suggestions as to how I might clean the throttle plate, or if there is another unrelated problem that might be causing the car to surge on takeoff.  It's getting worse and I'm afraid I am going to rear-end the car in front of me at a stop if I don't get it fixed soon.

3 Answers

73,035

First thing to do would be to get the vehicle scanned for any trouble codes. This would let you know what to look at. If there are any codes, write them down. I'm thinking the Throttle Positioning Sensor on the side of that Throttle Body, or the Gas Pedal (for lack of a term) may need to be replaced. But these things should show up with a code. You can go to a parts store to have the codes read.

40

Thank you very much for your response. I have an OBD II & CAN Scanner, which I am just now learning to use. I honestly didn't think it would show anything that would help because the check engine light never came on. If I'm not able to get any useful information from it because of my unfamiliarity with it, I will indeed to go AutoZone or O'Riellys and have the codes read. My Code Reader has the ability to transfer the data to a computer via USB port if this would be helpful.

73,035

Sounds like a decent scanner, just try using it on your car, never know, there may be a problem with the light.

Your Answer

Add photo

Related Questions

  • 2009 Hyundai Sonata surges at takeoff and acceleration 3 answers

    I have a 2009 Hyundai Sonata which has been a great car, having had only one problem with the starter in the seven years that I've owned it. But now, there seems to be a 'lag' in the throttle in takeo...

    2009 Hyundai Sonata GLS

    -

    Maintenance & Repair

  • My 2009 Hyundai Sonata won't start why? 1 answer

    Try replacing the battery with a 124R Walmart battery. 2009 Hyundai Sonata still won't start why?

    2009 Hyundai Sonata GLS

    -

    Maintenance & Repair

  • 2005 Hyundai Sonata acceleration issue 1 answer

    I have a 2005 Hyundai Sonata. I noticed today that when I stepped on the gas pedal while on the freeway while trying to pass a car when switching lanes, I saw the RPM shoot up to 3000 but my accelerat...

    2005 Hyundai Sonata Base

    -

    Maintenance & Repair

  • 2009 hyundai sonata blower motor needs replaced. 1 answer

    I need a blower motor on a 2009 Hyundai Sonata replaced. How difficult would this be to replace?

    2009 Hyundai Sonata GLS

    -

    Maintenance & Repair

  • Hyundai Sonata 4 answers

    I have a 2008 Hyundai Sonata that I have had for 5yrs. I love it & have never had any mechanical issues. However, on two occasions I have been either stopped and attempting to accelerate or driving ...

    2008 Hyundai Sonata

    -

    Maintenance & Repair

Sonata

Looking for a Used Sonata in your area?

CarGurus has 47,197 nationwide Sonata listings starting at $199.

ZIP:

Search Hyundai Sonata Questions

Hyundai Sonata Experts

#1 toDumbToNotKnow
toDumbToNotKnow
Reputation 1,570
#2 Tom Demyan
Tom Demyan
Reputation 1,330
#3 dandyoun
dandyoun
Reputation 1,080
View All

Related Models For Sale

Used Honda Accord
995 Great Deals out of 62,553 listings starting at $999
Used Hyundai Elantra
534 Great Deals out of 41,783 listings starting at $795
Used Toyota Camry
1,068 Great Deals out of 72,894 listings starting at $1,000
Used Kia Optima
483 Great Deals out of 28,713 listings starting at $2,500
Used Nissan Altima
1,126 Great Deals out of 74,548 listings starting at $999
Used Honda Civic
817 Great Deals out of 78,129 listings starting at $900
Used Ford Fusion
1,083 Great Deals out of 76,462 listings starting at $700
Used Chevrolet Malibu
1,217 Great Deals out of 78,026 listings starting at $1,500
Used Toyota Corolla
932 Great Deals out of 66,038 listings starting at $1,995
Used Hyundai Santa Fe
252 Great Deals out of 14,282 listings starting at $1,475
Used Nissan Maxima
325 Great Deals out of 23,646 listings starting at $1,750
Used Hyundai Genesis
96 Great Deals out of 2,481 listings starting at $5,200
Used Chevrolet Impala
567 Great Deals out of 34,674 listings starting at $1,000
Used Mazda MAZDA6
186 Great Deals out of 13,423 listings starting at $1,395

Used Cars For Sale

2018 Hyundai Sonata GLS For Sale
3 listings starting at $23,205
2014 Hyundai Sonata GLS For Sale
101 Great Deals out of 2,244 listings starting at $6,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.