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Old 11-27-2018, 07:21 PM
mr_robot mr_robot is offline
Join Date: May 2018
Location: NYC
Posts: 930
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Exclamation Overnight Cold Start Rough Idle N62 4.8iS

Ok, been trying to diagnose a cold start rough idle I've been experiencing ever since it has been getting cold here in New York.

It has new coil plugs and spark plugs from FCP's ignition service kit about a year ago.

Just got the VSS and all corresponding gaskets including the vanos seals done and at the same time rechecked the spark plugs for any fouling. Everything was good.

DME adaptation was reset after job was done as well. Car drives perfectly normal and strong otherwise.

I'm aware of the intermediate lever SIB and probably it is the issue but just want to understand something.

I get rough idle and sometime the CEL flashing with misfire codes P0300 and random cylinders, sometimes its cyl 2, 4, 6,7 or just 6 or 8, it's never consistent.

With that said it only happens after the car has been sitting over night (over 12 hours) next day going to work.

If it's my I.L. shouldn't it happen all the time for cold starts? For example, after I drive to work and come back (usually 6-7 hours later) it does not show these symptoms. It only seems to happen over a certain amount of time car has been sitting.

So if that is the case it could be a software/setting issue? Like what is different about 6 hours and 12 hours, what changes does the DME make to the valvetronics to go into a certain lift value?

I feel like I can bandaid fix this until I eventually get to do my I.L. if it's something I can change in the settings.

Thanks, any input is appreciated!
2005 Imola 4.8iS
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