2006 -2009 Legacy 2.5i Limited Rough Cold Idle

[06SubLegTx]

Hello,

 

Here is the situation: Yesterday I noticed and misfire coming from the driver side, and it went away.

 

I do run 93 octane fuel in it. Just put in new factory NGK spark plugs. I have only owned the car for 1.5 months. The care has 99,126 miles on it. I don't drive it hard..

 

Today, I went out and started it, there was a erratic misfire from the driver side. I took it for a drive, it seem to come and go, then on the way home the "Check Engine" light came on. Coolant Temp normal, Battery Normal 

 

I pulled the code using the Ignition Switch, Headlight, Trip/Odometer procedure>These were the codes came up with:

P0000, P0302

 

Also, code C0108 came up, I knew about this one and have already purchased Subaru Driver Side ABS Wheel Sensor and will put it on when I do my Bilstein B6 Struts and Shocks in a few weeks.

 

I will be doing all the Subaru Timing Belt components and Water Pump, & Oil Pump. in the next month too.

 

Is there a Really Good Fuel Injection Cleaner out there?

Edited March 29, 2017 by 06SubLegTx

[1 Lucky Texan]

does the car sit outside? I'm trying to recall but, recently it was dew-y in the morning (I'm in DFW area) so, I'm wondering if the plug wires or coil could have been moist, and the heat drove the moisture off after a few minutes. an 06 isn't terribly old, but it could need new plug wires I suppose. Also, any sign of oil on the plug boots when you swapped plugs? did the old plugs all look OK/the same?

 

some time when it's idling smoothly, use a plant mister to spritz water on the wires and note any missing that occurs - fairly sure sign of bad wires.

Edited March 29, 2017 by 1 Lucky Texan

[Caboobaroo]

With this era, I will always recommend doing the ignition wires with the plugs. I have seen many issues with reusing them and have also had issues with them new from Subaru. I only run NGK ignition wires on this era with almost no comebacks.

 

When you clear the engine memory, there is a possibility it will not relearn the idle (drive by wire throttle). If the idle is low and feels doggy off idle, remove the torque box and clean the throttle plate and body really well.

[06SubLegTx]

does the car sit outside? I'm trying to recall but, recently it was dew-y in the morning (I'm in DFW area) so, I'm wondering if the plug wires or coil could have been moist, and the heat drove the moisture off after a few minutes. an 06 isn't terribly old, but it could need new plug wires I suppose. Also, any sign of oil on the plug boots when you swapped plugs? did the old plugs all look OK/the same?

 

some time when it's idling smoothly, use a plant mister to spritz water on the wires and note any missing that occurs - fairly sure sign of bad wires.

Hey,

 

No it is in a garage always. The old plugs looked good when took them out, not burning any oil etc and they were all same make, model and no oil, etc. No oil on the boots when I change plugs out.

[06SubLegTx]

With this era, I will always recommend doing the ignition wires with the plugs. I have seen many issues with reusing them and have also had issues with them new from Subaru. I only run NGK ignition wires on this era with almost no comebacks.

 

When you clear the engine memory, there is a possibility it will not relearn the idle (drive by wire throttle). If the idle is low and feels doggy off idle, remove the torque box and clean the throttle plate and body really well.

I cleaned the throttle body about a week ago. I will get new wires (Subaru Only), put in Injector Cleaner (If I can find a good brand) and do a relearn procedure again.

 

Thanks for the help

[06SubLegTx]

Update: I found the issue(s)

1. The Plug Wires and the Coil are both the original ones that came on the car from the Factory in 2006

2. The #2 Spark Plug wire at some point either from the factory or when someone worked on it did not seat it all the way in the coil properly.

3. Because of item 2 was not done correctly and no Dielectric grease was used and the wire was not full seated, an electric arch was happening ever so slightly, this cause arching in the wire (I could see it and smell it), it also caused the coil port to get burnt to the point it was a pain just pulling out the old wire terminal end, and that deteriorated the conductor in the coil.

 

Now the car has New Plugs with proper gap, New Wires and New Coil