re: <E28> erratic idle

[John G.Burns <john@xxxxxxxxxxxxxxxxxxxx>]

> At the end of 1998, I replaced the exhaust on my 1985 535i with a
> Stebro system.  The O2 sensor was replaced at the same time.  Six
> months later, my idle has suddenly become erratic.

I'd suggest you check for a vacuum leak. Even the smallest
vacuum hoses (like the one to the top of the fuel pressure
regulator) can cause poor idle if they are cracked or loose
at the ends. A common culprit is the short hose from the
valve cover to the L shaped joint on the main intake hose,
it's made of too soft a plastic but is cheap to replace.

Also worth cleaning the idle control valve with carb cleaner
and adjusting your valves I suppose. I like to clean inside
the throttle body every year, it's surprising how much gunge
builds up behind the AFM and inside the idle valve to
manifold vacuum line.

- --
Who needs a life when you've got Unix? :-)   
Email: john@domain.elided, John G.Burns B.Eng, Bonny Scotland
Web  : http://www.unixnerd.demon.co.uk - The Ultimate BMW Homepage!

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