Q: When my car is at idle in park or neutral the Intake Air Control Valve fluctuates, causing the RPM's to do the same.

asked by on

When my car is at idle in park or neutral the Intake Air Control Valve fluctuates, causing the RPM's to do the same ranging from 800-1200 rpm's. If I unplug the IAC valve it stays at a solid RPM. Every sensor I've used had the same activity. So the PCM is making it fluctuate, what could cause that?

My car has 240 miles.
My car has an automatic transmission.

Hi there. It sounds as though the idle air control valve (IAC) may be sticking. It is not uncommon for carbon to build up in the valve, the computer will try to overcompensate to correct the slow reaction inside the IAC, and therefore the idle will fluctuate. It would be best to observe the commands from the PCM with a scan tool if you cannot physically see if there is carbon build up. A certified professional from YourMechanic can come to your car’s location to diagnose the idling problem and assist with repairs.

Was this answer helpful?
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. When my car is at idle in park or neutral the Intake Air Control Valve fluctuates, causing the RPM's to do the same.

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: Car hissing and overheating

This could be an indication of either a cooling system issue, or possibly a head gasket. Never check the cooling system on a hot engine, or when the system is pressurized, or serious injury may result. The cooling system will...

Q: Rough/ low idle, smells rich, and has a knocking sound near rear (like exhaust is rattling).

Hello. This may be potentially related to the mass air flow sensor or throttle position sensor. Initially, it may have been a faulty O2 sensor, but now since that has been replaced, that part of the system should work correctly....

Q: A high pitched noise when turning right.

The front end has many moving parts and if you are only hearing the noise when turning to the right and not to the left then the problem is either in the steering gear or the right side suspension is...

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 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.