New to e36

Sounds like a MAF or a vacuum leak, google the code to see what it says. then after you do that, report back with the info and we may be able to advise you on how to diagnose the problem. But we need need to know the essentials, Year Make Model, mileage, mods? recent maintenance? We've got no clue if you're in the wrong forum or if you have a 4 or 6 cyl E36 or if you drive a Ferrari.

Thanks again. The code comes back to secondary air pump. Seeing as it runs only on cold start ups for short periods, I don't know how it would give it a rough idle. Would unplugging the maf give me an indication if it were bad?

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Oh., and very sorry about the lack of info. 1998 328

Sent from my A500 using Bimmer App

120000 on the clock. Its the 6 cyl. Cold air intake, new plugs and that's about it f
Or mods or recent maintenance. again apologies for being lazy in my initial post.

the secondary air pump is a common failure, but you should first check the fuse for it and then try to jump the motor at the connector to see if it even turns on. there's also a check valve that stems off of the exhaust header that is prone to failure as well. These give the DME information and a signal at start up and at idle to lean out the fuel mixture and pre-heat the catalytic converter. Without this part, the DME sees no signal and resorts to a default mode when cold idling which can result in an erratic or jumpy idle depending on what the up and downstream O2 sensors are giving the DME for a reading.

Thank you very much, I'll check the fuse first thing. Then run down the list. Thanks for the explanation, I was confused how one was related to the other. I will locate the fuse and see where it leads.

Turned out to be dirty throttle body, dirty icv. Cleaned both and she purrrrrs like a kitten