My 2004 runs great, with the exception of its rough idle.
I am following the recommendations of AI and online research to replace the intake manifold gasket and PCV valve.
What level of testing should I do if this doesn't work?
Thank you!
A Checklist for Rough Idle
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William_Brown2000
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Thomas_Green78
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Is the engine light illuminated? Which codes are currently active or pending, if any?
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William_Brown2000
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On a strange note, yesterday the check engine light came on. Prior to that, it was idling rough.
This scanner is terrible. Code P0440 is the only one. The report describes it as a "minor leak."
I changed the PCV valve and gasket on the intake manifold this morning.
This scanner is terrible. Code P0440 is the only one. The report describes it as a "minor leak."
I changed the PCV valve and gasket on the intake manifold this morning.
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William_Brown2000
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Thomas_Green78
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That is helpful information, however I am unable to locate any reference to the rough idle in that code.
P0440 is defined as "a generic OBD-II diagnostic trouble code indicating an Evaporative Emission Control System Malfunction, typically caused by a large leak in the fuel vapour system or a faulty pressure sensor."
The engine has been idling poorly for how long?
I take it that when you gas it, it sounds smooth?
P0440 is defined as "a generic OBD-II diagnostic trouble code indicating an Evaporative Emission Control System Malfunction, typically caused by a large leak in the fuel vapour system or a faulty pressure sensor."
The engine has been idling poorly for how long?
I take it that when you gas it, it sounds smooth?
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Thomas_Green78
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William_Brown2000
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This car was just purchased by me a week ago. I got it, and it was idling rough. It becomes smooth as soon as the revs reach approximately 1200.
Right now:
-The PCV and manifold gasket were both replaced. Loosening the wire harness loom was going to be my plan to access the PCV. And thus, I disconnected each coil by removing its connector. Then I remembered that wouldn't get me anywhere, so I returned them.
-The vehicle started up after reassembly, but an error message indicating "missfiring on cylinder 1" was displayed.
Now I need to clean the coil contacts and give it another go.
Right now:
-The PCV and manifold gasket were both replaced. Loosening the wire harness loom was going to be my plan to access the PCV. And thus, I disconnected each coil by removing its connector. Then I remembered that wouldn't get me anywhere, so I returned them.
-The vehicle started up after reassembly, but an error message indicating "missfiring on cylinder 1" was displayed.
Now I need to clean the coil contacts and give it another go.
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Lucas_Smith97
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I would begin by looking at the STFT and LTFTs.
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William_Brown2000
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Alright, I reconnected a small hose that I had previously disconnected from the manifold/throttle body. Additionally, I sprayed down each of the coil connectors.
At least it isn't wasting energy anymore. During idle, PARK maintains a smooth speed of around 1000. However, when you shift into DRIVE, you'll notice a decrease in idle speed to around 600 and a slight vibration of the engine. It goes smoothly up to 900 or 1000 if I press the accelerator slightly while keeping the brake on.
They installed new motor mounts, according to the salesman (cough, cough). The one on the front passenger side is clearly brand new, and I can see it. The others are difficult to make out. Before I bought this car, I knew absolutely nothing about it. As a result, I am completely unfamiliar with the ins and outs of a 2004 Matrix.
At least it isn't wasting energy anymore. During idle, PARK maintains a smooth speed of around 1000. However, when you shift into DRIVE, you'll notice a decrease in idle speed to around 600 and a slight vibration of the engine. It goes smoothly up to 900 or 1000 if I press the accelerator slightly while keeping the brake on.
They installed new motor mounts, according to the salesman (cough, cough). The one on the front passenger side is clearly brand new, and I can see it. The others are difficult to make out. Before I bought this car, I knew absolutely nothing about it. As a result, I am completely unfamiliar with the ins and outs of a 2004 Matrix.