Skip the auto shop - Our mechanics make house calls

Q: High idling, engine misfiring, car jumps at high RPMs

asked by on

The car has a mileage close to 140,000 miles. It has idling issues. The car has no starting problems but it would start idling high. When I'm driving, the engine would misfire as well. The car would begin jumping when the RPM increases to around 2800. After having the codes read, the error codes that appeared indicated multiple cylinder misfiring. Up to now, I only had the spark plugs replaced, which didn't help. I was wondering what I should replace to improve the performance of my car. What do you suggest?

Hey there thanks for writing in about your 2002 Hyundai Elantra GT. The high idle is likely a bad idle air control motor (or air leak in the intake system). The misfire also may be caused by the factory spark plug gap being too great (.045"). Gap your plugs to .032" instead. To have this checked, have a qualified mechanic inspect the high idling and misfiring problems in order to have this correctly repaired and addressed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Clicking noise with steering wheel - 2011 Hyundai Sonata

There are three or more steering system recalls that may pertain to this vehicle. One is for the steering knuckle that was not made correct and not tightened correct during assembly and the loss of steering may be possible. The...

Q: AC blowing hot air after engine replacement

It sounds like your air conditioning has lost a charge. The refrigerant may have leaked, or they may not have charged the AC when they replaced the engine. I would have a technician come out and inspect your entire AC...

Q: #3 Misfire engine light

Yes, it can be an electrical issue. A misfire at a particular cylinder can be caused by ignition, fuel injection, mechanical issue, or vacuum leak. I'm curious why none of the dealership techs repaired it. Faulty sparks plugs, coils, or...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.