Rough idle on first start of day
#26
07-07-2023, 08:31 AM
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Join Date: Jul 2023
Location: Manassas Virginia
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Greetings Everyone, Nice read. I'm new to this forum and could use your assistance I have a 2011 MC S countryman N18 (70,000 miles) and have the same symptoms as described above. I have an engine light P0300 with occasional P0301-02-03-04 random pops up on the first cold start of the day; I don't always get a code. Similar to above the engine runs rough until the engine temp gets around 90-100 degrees when the high idle slowly resides to 800-900 rpms. At this point I can feel a small random miss. If I rev the engine to 2000-3000 rpms and let is settle down to idle the miss goes away. It could be a coincidences but I can duplicate the results the next day; after I let it set overnight. Otherwise it runs perfectly throughout the day after the first start.
So far I have replaced the coil packs, spark plugs, pumps: high and low pressure pumps, intake manifold seals, valve cover assembly with seals and just about censor attached to a wire with OEM products. Yep I have been down a lot of rabbit holes. On an interesting side note I did receive a new bad OEM bank 1 position 1 "O2" censor that gave me a vacuum leak code. I pressure tested the vacuum system and did not find a leak. So I replace it again and the code went away; this one hurt my head. I also noticed the misfire was during the "first cold" start sequence; the ECU indicated it was in the open system program. when it system closed and used all censors the problem appears to go away. ( So I took it the MC to dealer and had them flash the ECU which unfortunately did not resolve the issue). So it appears I chased another symptom.
My grey matter is slowly turning into mud. Is there something that could be sticking or can the timing chain be stretched and riding up the sprocket and settling down after the quick rev? I am really reaching here. Any help would be greatly appreciated.
Thanks
So far I have replaced the coil packs, spark plugs, pumps: high and low pressure pumps, intake manifold seals, valve cover assembly with seals and just about censor attached to a wire with OEM products. Yep I have been down a lot of rabbit holes. On an interesting side note I did receive a new bad OEM bank 1 position 1 "O2" censor that gave me a vacuum leak code. I pressure tested the vacuum system and did not find a leak. So I replace it again and the code went away; this one hurt my head. I also noticed the misfire was during the "first cold" start sequence; the ECU indicated it was in the open system program. when it system closed and used all censors the problem appears to go away. ( So I took it the MC to dealer and had them flash the ECU which unfortunately did not resolve the issue). So it appears I chased another symptom.
My grey matter is slowly turning into mud. Is there something that could be sticking or can the timing chain be stretched and riding up the sprocket and settling down after the quick rev? I am really reaching here. Any help would be greatly appreciated.
Thanks
#27
12-02-2023, 07:00 PM
Greetings Everyone, Nice read. I'm new to this forum and could use your assistance I have a 2011 MC S countryman N18 (70,000 miles) and have the same symptoms as described above. I have an engine light P0300 with occasional P0301-02-03-04 random pops up on the first cold start of the day; I don't always get a code. Similar to above the engine runs rough until the engine temp gets around 90-100 degrees when the high idle slowly resides to 800-900 rpms. At this point I can feel a small random miss. If I rev the engine to 2000-3000 rpms and let is settle down to idle the miss goes away. It could be a coincidences but I can duplicate the results the next day; after I let it set overnight. Otherwise it runs perfectly throughout the day after the first start.
So far I have replaced the coil packs, spark plugs, pumps: high and low pressure pumps, intake manifold seals, valve cover assembly with seals and just about censor attached to a wire with OEM products. Yep I have been down a lot of rabbit holes. On an interesting side note I did receive a new bad OEM bank 1 position 1 "O2" censor that gave me a vacuum leak code. I pressure tested the vacuum system and did not find a leak. So I replace it again and the code went away; this one hurt my head. I also noticed the misfire was during the "first cold" start sequence; the ECU indicated it was in the open system program. when it system closed and used all censors the problem appears to go away. ( So I took it the MC to dealer and had them flash the ECU which unfortunately did not resolve the issue). So it appears I chased another symptom.
My grey matter is slowly turning into mud. Is there something that could be sticking or can the timing chain be stretched and riding up the sprocket and settling down after the quick rev? I am really reaching here. Any help would be greatly appreciated.
Thanks
So far I have replaced the coil packs, spark plugs, pumps: high and low pressure pumps, intake manifold seals, valve cover assembly with seals and just about censor attached to a wire with OEM products. Yep I have been down a lot of rabbit holes. On an interesting side note I did receive a new bad OEM bank 1 position 1 "O2" censor that gave me a vacuum leak code. I pressure tested the vacuum system and did not find a leak. So I replace it again and the code went away; this one hurt my head. I also noticed the misfire was during the "first cold" start sequence; the ECU indicated it was in the open system program. when it system closed and used all censors the problem appears to go away. ( So I took it the MC to dealer and had them flash the ECU which unfortunately did not resolve the issue). So it appears I chased another symptom.
My grey matter is slowly turning into mud. Is there something that could be sticking or can the timing chain be stretched and riding up the sprocket and settling down after the quick rev? I am really reaching here. Any help would be greatly appreciated.
Thanks
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