04 xc70 flashing CEL while cold idling

ApplebeesBookClub · Post by **ApplebeesBookClub** » 18 Apr 2024, 15:53

New here, so hi! Just picked up an XC70. Apparently it had been sitting a while with old gas and didn't take long to start shooting misfire codes for just about every cylinder, including flashing check engine light. Replaced ignition coils, fuel filter/injectors right away (spark plugs were done just before sale) and its running strong however when started cold after 1-2 min it begins to idle a bit rough (~650 rpm), the same misfire codes come up and then CEL starts flashing. I can clear the codes and start driving and it will stop flashing, until stopped and idling again. This goes on for maybe about 10 mins until engine is fully warmed then no issue. Seems to have full power when accelerating and idles steady at 650 when at a stop. Any ideas? Previous car was a base 98 v70 so this is a bit foreign to my experience. Thanks!

Post by **MoVolvos** » 18 Apr 2024, 20:52

ApplebeesBookClub wrote: ↑18 Apr 2024, 15:53 New here, so hi! Just picked up an XC70. Apparently it had been sitting a while with old gas and didn't take long to start shooting misfire codes for just about every cylinder, including flashing check engine light. Replaced ignition coils, fuel filter/injectors right away (spark plugs were done just before sale) and its running strong however when started cold after 1-2 min it begins to idle a bit rough (~650 rpm), the same misfire codes come up and then CEL starts flashing. I can clear the codes and start driving and it will stop flashing, until stopped and idling again. This goes on for maybe about 10 mins until engine is fully warmed then no issue. Seems to have full power when accelerating and idles steady at 650 when at a stop. Any ideas? Previous car was a base 98 v70 so this is a bit foreign to my experience. Thanks!

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What are the codes? Could be sticky ETM butterfly, try cleaning it.
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ApplebeesBookClub · Post by **ApplebeesBookClub** » 19 Apr 2024, 00:18

P0300, 301, 303, 305 sometimes 304

Post by **MoVolvos** » 19 Apr 2024, 01:46

ApplebeesBookClub wrote: ↑19 Apr 2024, 00:18 P0300, 301, 303, 305 sometimes 304

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Air, fuel and spark. Assuming for now that your cylinders, plugs, coils and injectors/fuel are all good, you're left with air. Clean the ETM butterfly or look for other air related parts and connectors, since it's so many misfires at one time.
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