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Old 09-22-2011, 12:28 PM   #1
The Phenx
Scooby Specialist
Member#: 95823
Join Date: Sep 2005
Chapter/Region: MAIC
2003 Imprezza Wrx

Default Silly question - ghost missfires

SO heres my question.

I have had ghost missfires since I got my wrx back in 04 with 30k.

P301 p302 p303 p304

Its intermittent and nothing I have ever done has effected it one way or another with any permanence.

In the winter its not as frequent in the summer. In fact I have seen it go months without it showing up.

I have always attributed this to the lightened flywheel, and warmup cycles, and Ac.

During the 1st 2 min on a cold motor the idle is rough, which makes sense with the lack of inertia with the lightened flywheel. I also see it when running the AC at idle at a light. Somehow the drag/release the ac compressure clutch applies causes the missfire code as well.

The "missfire" is totally transparent, and doesn't effect the motor or performance in any fashion, in fact it runs as strong now as it always has. Same motor/tune/everything now has 214,000 miles so its obviously not hurting anything.

The only thing to degrade with age has been the gas milage.... it gets slowly less and less every year, (now avg 21-23 mpg)

Then the other day I was sitting at a light, and my ipod interface shut off untill I throttled up, this is far from the 1st time this has happened, and I got to thinking that over the years its happened a bunch.

So now I am wondering could a low output alternator (at idle speeds) be causing most of my issues?

Is coil on plug sensitive enough to have this be an issue?

Running upgraded wires across the board, and an optima redtop, and have 0 problems starting...but if the voltage is dropping too low to run the stereo at idle....
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