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Discussion Starter · #1 ·
Have just gotten my car back from the dealer; been experiencing a CEL for a misfire in cylinder 2. This is the third time it's been in, but the first time it was really looked at closely. In previous times, the CEL cleared when hooked up to the computer and the third-party warranty won't do anything when that happens.

The misfire seems to happen immediately on startup. Almost always in my garage at home, which is anything but cold during the summer. The car will start up, there'll be a noticeable shudder or vibration for 10-20 seconds, then the car drives normally for the rest of day. It was not happening perceivably every day, but maybe every 2-3 days while the CEL was on and I was waiting for a loaner to be available. The plugs were replaced at either 40k or 50k service due to the campaign regarding older plug style and this issue only began after they were replaced.

I've kept up with the other threads regarding misfire issues, but curious of the groups' thoughts regarding the initial diagnosis. When they pulled the plug, I'm told they noted carbon build up on the plug, plus some "fluid." They thought this was likely the cause of the misfire, but admitted it likely isn't a fix. A new spark plug replaced the fouled plug and I've had 4 days now without the CEL returning.

I did notice this morning a similar shudder upon start-up, but the CEL did not illuminate. I enjoyed the video that Sidwin posted in the other most recent thread about detonation issues, so I feel more comfortable understanding the problem. I'm mostly curious what is needed for CEL to illuminate for a misfire as I expected it to today, and if the new plug is simply a bandaid to get some more miles before the issue returns.
 

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your welcome.

you could also have a bad coil pack. if i was having misfire in a certain cylinder and the plugs were replaced, i swap coil packs and see if the problem follows. if it does than more likely bad coil pack or broken connector.
 

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It is hard to let dealer spend time on diagnosis. They only want to see the problem clearly and get solution from Volvo.

If it always happen every morning, you can let dealer keep the car overnight and diagnose in morning. Ignition pulse can be measured easily when the problem happens. It is good idea to swap ignition coils and see if the misfire cylinder also change.

Fusion · Red · T8 · XC60
 

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I have the same issue, CEL on morning while cold, engine runs rough for some seconds then fine all day.. I got cyl 4 misfire, I swap coils from positions to see if the issue moves to another cyl, if not could be a leaking inj.
 

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Discussion Starter · #5 ·
Picked up car yesterday after 4th visit for CEL. Previous attempts at repair were: new spark plug, removal of liquid around plug, and breather box bolts tightened. After leaving the dealer, got back on the interstate and started getting hesitation and shudders under acceleration. Few seconds later, car started getting worse and reduced engine performance message appeared and car went into limp mode. Got it back to dealer. Since 50k service, this car has been in the shop for cumulatively several months.
 

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your welcome.

you could also have a bad coil pack. If I was having misfire in a certain cylinder and the plugs were replaced, i swap coil packs and see if the problem follows. if it does than more likely bad coil pack or broken connector.
That would be my first suspect cause. It also sounded like oil and/or gas leaked down onto the plug once the engine is shut down, causing misfire when started later? That would seem like a significant leak. However you did mention that the plug required cleaning a liquid away and had carbon build up (the result of burned oil?) Perhaps a valve guide is leaking? It makes sense to let the dealer have the car to start up after sitting all night. They could pull the plug after letting it sit all night to see if it is coated with anything. Interesting dilemma, best of luck.
 

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The number two cylinder and it's coil pack is prone to flooding with oil (as it's the only plane the oil can go) when adding oil (eg while changing oil service) and the tech misses the hole or spills. I had to replace my number two coil twice because of this. Every time went to change it along with the spark plug it was filled with oil. Pull the cover off and check it out. Might be the same issue.
 

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The number two cylinder and it's coil pack is prone to flooding with oil (as it's the only plane the oil can go) when adding oil (eg while changing oil service) and the tech misses the hole or spills. I had to replace my number two coil twice because of this. Every time went to change it along with the spark plug it was filled with oil. Pull the cover off and check it out. Might be the same issue.
I think you are right on. Given the car has 50,000 miles suggests it has been in for several oil changes. So that would make sense that when adding oil a slight miss might result in oil seeping towards and affecting #2 coil pack and spark plug. When I have changed my oil in-between service visits I always remove the soft foam rubber engine cover as it seems that spilling oil would be relatively easy without doing so. Even with a funnel it is not easy and requires that you take your time. Thank you for your insight.
 

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Discussion Starter · #9 ·
I believe the oil was appearing even after being cleaned out and plug replaced , so that might discount the theory a bit. Never say never.
Dealer believes it's a faulty fuel injector and is replacing on Monday.

Don't know that I've read many folks with misfires/reduced engine performance report injector trouble, so we'll see!
 

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Discussion Starter · #10 ·
Warranty replaced all four injectors; picked up on Friday.
Dealer very confident that it's solved as computer said it's gone from hundreds of misfires per mile, to almost zero.
 

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Interesting result. By the way what type of gasoline do you purchase? Is it a tier one or off brand? Once injectors get fouled they are hard to clean up by just using tier one gasoline. However, that still does not address the oil and soot on the plugs. There could be several things happening making this problem much more complex. Could be that the oil was the result of overflow during filling. The CEL could have been the result of a faulty injector. I am sure they validated the coil pack was ok, as that would have been cheaper than replacing the injectors. Keep us advised, thanks
 

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plugs, injectors, coil packs, leaky superchargers...the drive-e is a winner!
 
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