This afternoon my 2007 V50 (non turbo) 99,600 miles, started sputtering slightly and didn't idle smoothly. The car start normally, there is no difficulty in starting it. I checked the codes when I got home and they came up P0301 (cylinder 1 misfire) and P0300 (multiple cylinder misfire). Possible causes are:
Spark Plug Wires
Coil or coil pack
O2 sensor
Fuel Injectors
EGR Valve

I just had new plugs put in about 2 months ago. In this car each cylinder has a coil. I doubt all would go bad at once the same goes for the fuel injectors. What could be the most likely cause of these codes?

also what is the relationship between cylinder 1 and all cylinders misfiring? would 1 misfire first and then all in a cascading manner?

I do most of the work myself.

Any thoughts?
John 98 v70, 07 v50, 91 245

Last night I put some techron fuel injection cleaner in and topped off the tank and cleared the code out (start simple). I drove it about 30 miles without incident and then it sputtered again. I ran the codes again and this time I only came up with P0301 code and not the P0300 as I did yesterday. It starts easily but hesitates when I rev the engine. I will try moving the coil pack to cylinder 3 and see if it impacts the codes.

Thanks for your time.

Since you're going to dig in there and have the coil off anyway, I'd go ahead and move the spark plug also, but not to the same cylinder that you move the coil to. You need to get a look at that spark plug anyway.

Chris, I just completed moving the coils (1 to 3 and 3 to 1). If it codes P0303 then I know it is the coil. However, if it still codes P0301 then it points to the plug. That is my logic. However, please educate me as to the benefit of moving the plug too from your point of view. What should I look for with the spark plug? I hit a deer which knocked the head light alignment out (whew, that was all). I took it to the dealer to align and to put new plugs in, so I hope the dealer installed the right ones.

I did find one curiosity when I made the switch. The number one hole and coil boot was all dirty with rusty looking residue, the number 3 hole and boot was clean. I am wondering what could have run down there. In october I had the timing belt changed. I am wondering if when the coolant reservoir was moved out of the way some coolant could have spilled and run under and down around the boot. Perhaps some water from washing the engine bay got under the spark-plug cover via the timing belt cover. Perhaps the number one spark plug is faulty because of that.

We will see

It is dark out, so now is the perfect time to raise the hood and look at the wires and coils to see of there is any arcing. A rusty #1 wire would also do it.

If you still get a p0301, and the coil and plug are good, then you will need to do a compression test.


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My name is Klaus and I am a V♂lv♂holic

As I said I switched coil one and coil 3 and cleared the codes. I drove the car all day without incident and no fault codes registering. Perhaps it was just a loose connection. I wish it would make up its mind.

Thanks for all of your consideration and input.

John

Any one of your theories as to how the #1 hole got moisture in it sounds logical.

The reason I suggested moving the plug to a different cylinder was that just in case the plug WAS the culprit, moving it to #4 for instance would have caused a P0304 code. That's why I said don't move it to the same cylinder that you move the coil to - so you could differentiate between which part, coil or plug, was the problem.

It may just be that moisture in the #1 hole had caused a bad connection between the coil and spark plug.

Chris is correct. Move the coil pack from #1 to #3 and see if the p0301 turns into p0303, if it does, replace the coil. You can buy a coil online for about $50 or less:

http://www.fcpeuro.com/products/volvo-ignition-coil-c30-c70-s40-s60-v50-v70-30713417

There is normally no need to change all of them at once, but it is nice to have a spare.

All Volvo turbo engines need copper core plugs for long life and they are gapped at .028
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My name is Klaus and I am a V♂lv♂holic

"...what is the relationship between cylinder 1 and all cylinders misfiring?..."

"Multiple Missfires" doesn't necessarily mean ALL cylinders are missfiring.

Since the plugs were recently replaced, that would probably be my first suspect. It wouldn't be the first time that new plug(s) went bad prematurely. Also, are you sure the correct kind of plugs were installed? I'm not at all familiar with your model, but in most other Volvos I've owned I had the best luck with the $2.00 NGK copper cores.

You could try a new set of plugs, carte blanc, just to see what happens. Or if you want to experiment, you could move the #1 spark plug to the #2 cylinder and move the #1 coil to say the #3 cylinder. Then clear the codes and run the car. See if the error code moves to cylinder #2 or #3.