Over the past year or two I've noticed my car sometimes has elevated RPMs at idle. This happens very rarely, maybe like once or twice a month.
It is not a rough idle, the RPMs are not fluctuating wildly. It gently goes up for a little while, then gently comes down for a little while, and this repeats until I shut the car off.
The RPMs will go up to about 1100, and then drop back down to the normal 700.
The check engine light is not coming on, there are no lights on at all.
This does not happen on cold start. I've only seen this happen after driving around for a while, maybe a few hours. It only happens in PARK, not in neutral. When it happens it's usually when I come home, or in between appointments. There are no rough vibrations coming from the engine.
I recently put in a new PCV valve but these elevated RPMs used to happen way before the new PCV valve was put in.
What is very weird is that when I come home and put the car in park, and notice the RPMs going up at idle, when I press the brake pedal the RPMS come back down to 700. When I release the brake pedal, the RPMs will go back up to 1100. As you will see in the 2 videos I have linked to below. How is it that pressing the brake makes the RPMs come down to 700, but then upon releasing the brake the RPMs go back up to 1100?
When I press the brake the RPMs come down to 700, and stay there until I release the brake, then they go back up to 1100.
Also, I noticed that if I don't touch the brake at all, the RPMs will still fluctuate on their own. Without touching the brake, the RPMs gently go up to 1100, then gently come back down to 700. In this scenario, you'll notice that as the RPMs drop to 700, they then quickly go back up to 1100. Again, this is without touching the brake.
In one of videos, if you turn the volume up really high you can hear me pressing and releasing the brake.
The emergency brake has no impact on RPMs. Just regular brake.
I've been observing this RPM fluctuation for a year or 2 and finally decided to come here and see if it's a problem.
using the brake
WITHOUT touching the brake
I spent some time reading about this online but couldn't really find anything identical to this issue. Most of the literature out there in regards to fluctuating RPMs at idle is in regards to a ROUGH IDLE. Which, this doesn't seem like a rough idle, does it ?
Fuel consumption is normal, the car is not stalling. There seems to be no other symptoms.
It would be nice if the fix was something simple like the MAF mass airflow sensor. I am thinking of ordering a new MAF sensor but they are $150.
This weekend I will take apart the intake tubes and take a look at the throttle body. Maybe it needs a cleaning.
It is not a rough idle, the RPMs are not fluctuating wildly. It gently goes up for a little while, then gently comes down for a little while, and this repeats until I shut the car off.
The RPMs will go up to about 1100, and then drop back down to the normal 700.
The check engine light is not coming on, there are no lights on at all.
This does not happen on cold start. I've only seen this happen after driving around for a while, maybe a few hours. It only happens in PARK, not in neutral. When it happens it's usually when I come home, or in between appointments. There are no rough vibrations coming from the engine.
I recently put in a new PCV valve but these elevated RPMs used to happen way before the new PCV valve was put in.
What is very weird is that when I come home and put the car in park, and notice the RPMs going up at idle, when I press the brake pedal the RPMS come back down to 700. When I release the brake pedal, the RPMs will go back up to 1100. As you will see in the 2 videos I have linked to below. How is it that pressing the brake makes the RPMs come down to 700, but then upon releasing the brake the RPMs go back up to 1100?
When I press the brake the RPMs come down to 700, and stay there until I release the brake, then they go back up to 1100.
Also, I noticed that if I don't touch the brake at all, the RPMs will still fluctuate on their own. Without touching the brake, the RPMs gently go up to 1100, then gently come back down to 700. In this scenario, you'll notice that as the RPMs drop to 700, they then quickly go back up to 1100. Again, this is without touching the brake.
In one of videos, if you turn the volume up really high you can hear me pressing and releasing the brake.
The emergency brake has no impact on RPMs. Just regular brake.
I've been observing this RPM fluctuation for a year or 2 and finally decided to come here and see if it's a problem.
using the brake
WITHOUT touching the brake
I spent some time reading about this online but couldn't really find anything identical to this issue. Most of the literature out there in regards to fluctuating RPMs at idle is in regards to a ROUGH IDLE. Which, this doesn't seem like a rough idle, does it ?
Fuel consumption is normal, the car is not stalling. There seems to be no other symptoms.
It would be nice if the fix was something simple like the MAF mass airflow sensor. I am thinking of ordering a new MAF sensor but they are $150.
This weekend I will take apart the intake tubes and take a look at the throttle body. Maybe it needs a cleaning.
