srudiger

i just picked up a 2000 328ci bmw with the e46 inline six. When i went to cold start it for the first time it idle's fine for about a minute, then every ten seconds or so the rpm's drop and jump back up. it's not back to back drop/jump but once it warms up it stops and rides like a dream?? any suggestions?
any help will be greatly appreciated thnx va

Fabrik8

That sounds like it's got something very minor causing that. Often a slightly clogged idle air control valve (input screen) will do that on most cars; the flow is being restricted just enough to be different from what the ECU is expecting. During cold start, the greater airflow needed for high idle tends to highlight things like that.

I'm assuming there aren't any problems idling once the engine is warmed up?

I can't really you help with the specifics of that engine, but most modern engines are virtually identical in how they work so the troubleshooting theory is virtually identical too.

srudiger

yes once it's warmed up runs perfect. thnx for the help i will check it out tom. and see if it fixes it