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Car slight jerk at idle and jerks when pressing throttle

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hi,

 

have a problem today. hope you guys know what it is. kia forte 1.6sx of 5 years and 4 months old, 77Kkm mileage.

 

Today the car jerks at idle at red light, and i can see that RPM slight jumps up and down, like 400rpm - 700rpm. Usually it is idle at 400rpm without up and down. The jerk is about every 4 seconds, not constant jerking. can feel the car tremble.

 

When i press the throttle to accelerate during travelling, the car will jerk again, and does not accelerate instantly as normal. after a while it accelerates to a higher cruising speed, then it's OK again. During jerking, the engine light flashes like 10 times. when the jerk stops, engine light becomes off again. I just changed engine oil and engine filter 2 months ago.

 

Is this worn spark plugs, or ATF due to change (coz it's been a while), or both, or something else?

 

Thanks.

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Could possibly be due to spark plugs or high tension cable needs to be replaced.

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I'm not very experienced, but it does sound like a misfire.

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Guess work is only good for symptoms common to a model.

 

Use OBD to isolate first. Go to workshops with the right tool.

 

 

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My car started shivering today.

Diagnosis - ignition coil.

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Yeah. I also think it's misfiring. Worn spark plug won't activate CEL.

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Buy a cheap OBD2 bluetooth adapter from Dealextreme, I got one from them as well and it works great. For engine codes you can google them to get a better idea of what they mean as some code names are not clear.

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it is misfiring from the code. initially p0300. but after changing coil and spark plugs, it still has misfiring with p0302. 2nd cylinder misfiring. just hope it is not something seriously bad and will have to spend a bomb. still yet to diagnose what exactly it is.

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it is misfiring from the code. initially p0300. but after changing coil and spark plugs, it still has misfiring with p0302. 2nd cylinder misfiring. just hope it is not something seriously bad and will have to spend a bomb. still yet to diagnose what exactly it is.

Hi.. do u still remember at the end what is the cause?

I am experiencing the same issue on my ride.

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Hi

 

Need help

There is this roaring sound from engine compartment when car move off from stationary sounded very rough.

Normally about 2000rpm onwards.

When ok highway which rpm is normally below 2000 there is not significant sound.

 

This roaring sound will sometimes disappear and it will be smooth like baby but most of time it is around.

 

Abit like modified exhaust sound but my car is stock.

 

When in neutral and accelerate there is no sound thus engine should be fine and exhaust not leaking.

 

Honda vezel 2015, 60k mileage

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Hi

 

Need help

There is this roaring sound from engine compartment when car move off from stationary sounded very rough.

Normally about 2000rpm onwards.

When ok highway which rpm is normally below 2000 there is not significant sound.

 

This roaring sound will sometimes disappear and it will be smooth like baby but most of time it is around.

 

Abit like modified exhaust sound but my car is stock.

 

When in neutral and accelerate there is no sound thus engine should be fine and exhaust not leaking.

 

Honda vezel 2015, 60k mileage

 

Let me make a wild guess , likely a worn bearings from the drive train.

Could be ac compressor , tensional pulley , alternator ....

 

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Let me make a wild guess , likely a worn bearings from the drive train.

Could be ac compressor , tensional pulley , alternator ....

 

I was guessing the drive train bearing, is it normally located along the moving shaft linked to the wheel bearings? I notice my wheel bearing is also a bit wear out. But weird that the sound only appears when I accelerate

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I was guessing the drive train bearing, is it normally located along the moving shaft linked to the wheel bearings? I notice my wheel bearing is also a bit wear out. But weird that the sound only appears when I accelerate

 

From pass experience , roaring sound that comes n go (intermittent) normally caused by bearing.

Get it check by experienced mechanic.

 

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hi,

 

have a problem today. hope you guys know what it is. kia forte 1.6sx of 5 years and 4 months old, 77Kkm mileage. 

 

Today the car jerks at idle at red light, and i can see that RPM slight jumps up and down, like 400rpm - 700rpm. Usually it is idle at 400rpm without up and down. The jerk is about every 4 seconds, not constant jerking. can feel the car tremble.

 

When i press the throttle to accelerate during travelling, the car will jerk again, and does not accelerate instantly as normal. after a while it accelerates to a higher cruising speed, then it's OK again. During jerking, the engine light flashes like 10 times. when the jerk stops, engine light becomes off again. I just changed engine oil and engine filter 2 months ago.

 

Is this worn spark plugs, or ATF due to change (coz it's been a while), or both, or something else? 

 

Thanks.

 

Hi,

 

I am having the same problem. May I know what is the actual cause? And how much is the cost to repair?

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Hi,

 

I am having the same problem. May I know what is the actual cause? And how much is the cost to repair?

Likely one of the Ignition coils or spark plugs, one piece cost about $30 but with labor maybe a bit more, spark plug is cheap . You can just change out the defective one.

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I had this problem twice before. It is either the coil to the spark plug. The latter is cheaper to fix. My Mech recommended to replace the plugs first. It solved the problem. 

On the second occasion, after about 70K kms, it happened again. I straightaway bought a set of spark plugs to replace. The problem was solved again.

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Posted (edited)

I had this problem twice before. It is either the coil to the spark plug. The latter is cheaper to fix. My Mech recommended to replace the plugs first. It solved the problem. 

On the second occasion, after about 70K kms, it happened again. I straightaway bought a set of spark plugs to replace. The problem was solved again.

 

I used a OBD II scanner and it specifically showed bank 3 misfired. 

 

I swopped the ignition coil from the 3rd  to 1st bank.

 

Start the engine and checked again and it showed 1st bank misfired. 

 

This confirmed it's a spoiled ignition coil. Bought one and replaced it together with 6 pcs of SP that was pretty worn out.  

Edited by Hamburger
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