Revs dropping randomly at idle, car jerks

135

Asked by May 19, 2015 at 05:07 PM about the 2004 Hyundai Elantra GLS

Question type: Maintenance & Repair

As a disclaimer, the car's an 04 Hyundai Elantra GLS sedan with the 2.0L 4-cylinder.

So, sometimes when I'm stopped, and the car's in either drive, park, or reverse (never happens in neutral that I can tell, or above 10mph), there'll be that little jerk that feels like someone just kicked the back of your car. The wheels don't move, but it feels like the body moves forward about an inch and then comes back. Whenever this happens, the revs drop between 100 and 250, and the strength of the jolt, for lack of a better word, is directly related to how much the revs drop. The car idles around 700 normally, but has dropped as far as 400 when this has happened. My guess is that the car's stalling, but I can't figure out why. If it was the transmission slipping, it'd happen in the other gears, right? All my fluids are fine, including transmission fluid. It can't be a spark plug, or it would be happening constantly instead of just once in a while. I wouldn't think it's the throttle position sensor, as acceleration is smooth and it doesn't do it while just coasting with my foot off the gas. If I had to guess, it's something with either a spark plug wire or one of the coil packs that the spark plug wires connect to. I just bought a new set of wires, so I'll probably install them in the next couple days and I'll try to remember to update this with whether or not that fixes the problem. The only other thing that comes to mind is the evap canister - it could need replacing, so I'll also detach the sensor for that and see if that's the cause, assuming the new wires don't solve it.

But anyways, I was just curious if anyone has had a problem like this. The car's got a tad over 78k miles on it, and I've never had anything need done outside of regular maintenance.

2 Answers

975

input output sensors or bad connection with fuel pump relay front of car the fuse box under the engine hood pull fuel pump relay out bend pins a little to make relay tighter in socket relay gets hot well driving weakens socket and makes bad connection to relay,

2 of 2 people found this helpful.
135

Replacing the spark plug wires seems to have solved the problem, there was a crack in the boot of the #3 cylinder's wire.

Your Answer

Hyundai Elantra Experts

  • #1
    pittgirl
    Reputation
    2,020
  • #2
    Carrie Shelton
    Reputation
    1,390
  • #3
    Pirdman
    Reputation
    1,170
View All

Related Models For Sale

Used Hyundai Sonata
855 Great Deals out of 58,957 listings starting at $1,500
Used Honda Civic
775 Great Deals out of 68,008 listings starting at $999
Used Toyota Corolla
967 Great Deals out of 65,080 listings starting at $850
Used Toyota Camry
998 Great Deals out of 101,128 listings starting at $300
Used Honda Accord
1,202 Great Deals out of 74,727 listings starting at $561
Used Hyundai Accent
264 Great Deals out of 13,421 listings starting at $1,500
Used Nissan Altima
1,220 Great Deals out of 89,015 listings starting at $1,500
Used Kia Optima
501 Great Deals out of 36,048 listings starting at $1,995
Used Mazda MAZDA3
433 Great Deals out of 28,189 listings starting at $899
Used Ford Focus
814 Great Deals out of 61,808 listings starting at $1,150
Used Nissan Sentra
763 Great Deals out of 56,593 listings starting at $600

Used Cars For Sale

2014 Hyundai Elantra GLS For Sale
50 listings starting at $7,983

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.