1990 535i E34 hunting idle

I'm the proud owner of a 1990 535i E34 but since i bought it 2 months ago, i've had a problem with hunting idle. this is my first BMW so i'm really not familiar with it's quirks. i've had the fuel injectors and
lines checked and cleaned but it's still "gurgling". one mechanic said it sounded like the gas:oxygen mixture was too rich. he also mentioned something about a lambda sensor. is he right? what else could it be? pls HELP!
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I don't think your car has a lambda / O2 sensor, but I may be wrong. UK cars built in 1990 don't need a catalytic convertor and I don't think yours has one. Our 1990 E34 Alpina B10 didn't.
It's much more likely to be a vacuum leak due to a split air hose or a sticking idle control valve (cheap).
I'd also be very tempted to fit a new distributor cap and rotor arm. There's a good chance yours are 16 years old! New ones can make a big difference to mpg and top end power.
These cars need a valve adjustment every 24k miles, that's worth a go too.
It doesn't sound like your mechanic is too familiar with BMWs. You'd save money in the long run by going to a specialist, see my site's UK garage review pages.
--
Who needs a life when you've got Unix? :-)
Email: snipped-for-privacy@unixnerd.demon.co.uk, John G.Burns B.Eng, Bonny Scotland
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John, John, John. Even your web site notes our stricter pollution requirements. No US BMW since the late '70's has not had a cat. The changeover for the E12/M30 was the 78 to 79 model year IIRC. I don't believe any 6 or 7 ever had a non-cat motor. As near as I can tell, the OP is in the US.

Absolutely agree.

FloydR
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Floyd Rogers wrote:

And on top of all that, the 3.5l M30 isn't known for having a particularly smooth idle. If it stays *in the neighborhood* of 700-900 most of the time and it runs all right all the rest of the time, you should normally be satisfied. -- C.R. Krieger (Been there; done that)
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I THINK he said his car was a 535i SE, SE is a UK designation. I may be wrong :-)
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See, if you were using a *real* newsreader like OEX rather than the Unix/Linux stuff you use, then you could just go back and see that he didn't. ;->
LOL, FloydR
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In addition, possibly inlet manifold gaskets as well.

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