Skip the auto shop - Our mechanics make house calls

Q: Car is not idling smoothly

asked by on

My car is not idling smoothly. While idling, it bounces between 700 and 900 RPM. I have replaced the wires, spark plug, and fuel filter. I think I checked the hoses. I also just changed the upper and lower manifold seals. I have noticed that there are small fluctuations when I am driving on the highway while using cruise control and on flat land. I want to solve this myself and not go to a mechanic. Any ideas?

A: Hello. This is typically caused by either a...

Hello. This is typically caused by either a dirty throttle body or a bad throttle position sensor. I typically start by cleaning out the throttle body. That will usually take care of the problem. If it persists, I will use a scan tool to monitor the throttle position sensor signal to see if it is failing. That should be the problem. It can also be the air flow meter, but that is not as common. If you want to have someone take a look at it, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your idling issue.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Warning lights come on while backing down a hill, Infiniti G25

There is a short somewhere causing the lights to work intermittently. However, to provide more insight as to where the short might be, I would need to know exactly which lights are illuminating intermittently. I'm guessing that it is not...

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

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...

Q: When I press the gas the car does not accelerate but instead makes a high rev noise.

Hello. If the car is in "Drive" and you attempt to accelerate from a standing start and yet the car does not move forward, you have a problem with the transmission (perhaps the linkages) and/or torque converter. The misfire code...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...