Replaced Coils and Spark Plugs - STILL Misfiring

[coastalcraig]

First - THANK YOU for any assistance in this matter. I have a 2009 V70 3.2 L. About 9 months ago, the car was driving along fine and a mile later I couldn't move it 10 feet. A Volvo specialist mechanic told me there was some electrical problem and he had to replace the coils. He did that plus oil for $1500.

Now the engine runs very rough below 2000 RPM but seems to run smoother at higher RPM. I have trouble driving highway speeds though.. I purchased an OBD2 tester.

I visually inspected all of my fuses and they look fine. I replaced all of the spark plugs and coils myself. After I did this, my OBD2 tester seemed to mostly indicate misfire only on cylinder 1. This is somewhat random, however because the longer time I continue on, the more other cylinders also report misfires. I looked at as many YouTube videos as I could find and I found a gentleman running the engine and putting a 12v tester into the plug for the coil. In the video, he demonstrated how the light on the tester would blink every time the PCM sent current to the coil. His plug looked like it only had 2 conductors. Mine has 4 conductors.

At any rate, I did the same thing. 1 of my 4 conductors shows current when the engine is running. Problem is that my light doesn't seem to blink. My tester light just visually appears to be on 100% of the time. I am not a mechanic. That said, I can't really afford to spend $1500 every 6 or 9 months to take the car to a mechanic.

My wife was Swedish and this was her car. She passed away and I can't bring myself to give up on this car. I would be grateful for guidance from some of you Volvo wizards.

[AVOIT17]

Hi - It appear as this mechanic you mentioned did not fix the problem. This does not look good in the sense that he maybe not qualified - so I would be suspicious of his work. If you do not work on cars yourself you need to find a trustworthy qualified mechanic.

You can diagnose the sparkplug and coil on the problematic cylinder by switching them with another cylinder. If the problem follows either the sparkplug or the coil then you know that they are the problem. If despite switching sparkplugs and coil the problem persist then you know that the problem is from something else - possibly a plugged fuel injector. Note to diagnose you need to switch only one part at the time. Only the spark plug or only a coil - not both at once.

There are other dysfunctions that can cause misfiring - it could be the module or a bad wire or connector - diagnosing the problem is the most important part. Consider that the one who diagnoses the problem does not have to be the one who repairs the car. Spend the money on a reliable expert mechanic for diagnosing. Then figure after how to go about repairing - maybe you can do it yourself!

I would minimize driving the car until this problem is fixed.

[MoVolvos]

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Are you near either shop in CA?
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https://www.yelp.com/biz/montclair-auto ... -oakland-2
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https://www.yelp.com/biz/independent-vo ... lnut-creek
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