Skip the auto shop - Our mechanics make house calls

Q: Car is idling up and down while either parked or when driving.

asked by on

I recently replaced my Started in my vehicle. Since I got it back on all of a sudden its idle was off. I took it to Oriely's and had them put it on their computer. It came out with 4 error coded. It ended up being a sensor called oem or something like that I paid for the sensor and replaced it while I was there. It honestly went from its rough idle and it going up and down in rpm's randomly to perfect. There was no noise whatsoever I could barely hear the engine we thought it was fixed so he reset my computer check engine and let me go home. I drove the car and it was perfect but a few hours later it started acting up again. I took it the the local chevy dealer and they said that they put it on a computer and there was no issues. they said it was due to Carbon build-up, so I paid 200 and some dollars to get the engine cleaned. Guess what it did nothing other than it not idleling quite as low when the ac kicked on. essentially nothing has got fixed what is the issue?

My car has 160000 miles.
My car has an automatic transmission.

Hi there. I believe O’reilly’s sold you an IAC (idle air control valve) from the description you have given. OEM is the acronym for original equipment manufacturer. Seems odd that it was only fixed for a couple of hours. Sometimes aftermarket parts will not perform as well as factory (OEM) parts.

Carbon build-up could cause idling problems. Assuming the Check Engine Light has not come back on, means the computer is not recognizing a fault. If the idle is stable and just feels rough, I would look into the possibility of engine mounts being at fault or maybe a tune-up that is due. I recommend having your vehicle’s rough idle inspected and diagnosed by a certified technician, like one from YourMechanic.

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
  1. Home
  2. Questions
  3. Car is idling up and down while either parked or when driving.

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: No power

I would recommend double checking the battery installation to make sure that everything was connected properly. If you would like to have your vehicle inspected to deterimine why these issues are occuring consider YourMechanic, as a certified mechanic can come...

Q: Rough idle, its "studdering when i accelerate"

Hi there. This may be a sign of a failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected...

Q: Replaced DVD player & SUV's interior lights quit working

Hello. It sounds like a fuse may have blown or interior light wiring may have been damaged. It is also possible that the bulbs have blown out. First check the DVD player wiring where the DVD player is mounted and...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...