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2005 Malibu 4Cyl Idle Issues

28793 Views 15 Replies 4 Participants Last post by  Mrfixit

When starting car the idle runs rough and then will eventually die. Will die at stop lights. If I press the gas while at a stop I can keep it running by shifting to neutral or going to park.

Err Codes: P0300, P0442

What I have done since(with no resolution):
1. Cleaned Throttle Body
2. Cleaned the Mass Air Intake Sensor(in front of air filter)
3. Replaced Ignition Coil
4. Replaced Spark Plugs
5. Replaced wireset
6. Replaced Ignition Control Module
7. Checked the Fuel line pressure and is registering 58-60psi.

My ideas are

1. The Throttle Position Sensor(TPS) is bad an thus will need to replace the entire throttle body.(Autozone does not have the Throttle Body).
2. Intake Manifold leak/vacuum issue

I am not a mechanic, fast learner, trying to resolve this.

Any help is very appreciated.
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Thank you for you reply!

The spark plugs had a little wear, I will take pictures this evening and post links to those. I went ahead and replaced them though since I was looking.

I do not have "freeze frame data" other than there were vacuum leak or multiple misfires.

The car has 78k. The car was rear ended late last year, but was very small damage and was not high speed.

Yes, it suddenly showed up. This happened about two weeks ago, which the weather got a lot colder too here in Columbus, Ohio. The car is not parked in a garage and thus bares the elements. This is my sister-in-law's car and thus I asked her how if she lets it warm up much when it is cold and a couple minutes if at all is what I am gathering.

If I were to test for a leak, how would I go about doing this? What spray or substance and where to apply it?

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Got Throttle cleaner! :) Will check this out this evening.

When this started she had 1/4 tank or less and when and filled up(regular unleaded) and then also put in fuel cleaner of STP. From working on it I filled it up with a higher octane gasoline.

Thank you
I used throttle body cleaner tonight and sprayed around the intake manifold along with the hose and noticed nothing different. I checked the torque on the spark plugs to verify I had 15lbs torque. I unplugged the mass air intake sensor and started the car and it would run without stalling. When I connected the mass air intake sensor back up it seemed to run better until I took it on a test drive.

Question: Does the 4 cylinder engine even have a PCV valve? If so where is it?

Here are the old spark plugs:

New spark plugs:

I took a small video without mass air intake sensor:

With mass air intake sensor:
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Okay, everything seems fine still. I am thinking of going ahead and replace the Mass Air Flow Sensor. However, I went to buy a T20 Security bit however it does not fit. The bit I bought has 6 grooves(hex) and the security screw on the MAF only seems to have 5 grooves. Do you know what tool and size I need in order to take the MAF off and replace?
Nevermind, finally figured i out.


Okay, so I am waiting on the security bit(I am positive about tool now), only some models of the Malibu have it. Don't ask me why! ;)

So I noticed that if I start the car, it will run okay in PARK albeit the engine still vibrates and such. As soon as I put it in DRIVE then it acts sporadically. Whatever that means I have no clue, but thought it was worth mentioning.
When I say I put it in DRIVE I mean I have the break on and am just sitting there. Same occurs when test driving and I come to a stop sign or light.
Just an update. Finally fixed. It turned out the timing chain had some bad links, the tensioner needed replaced and the guides were all missing. Replaced them and the car is running like new. This is why I was getting misfires. I also got computer reflashed with current version.

I had to go to the dealer on this one as I am not comfortable doing that level of work.
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