1993 e36 325 surging / flatness

[eliot]

Wives 325 has developed a flatspot or surge at pretty much any throttle angle. Key thing ive noticed, is that the MPG needle keeps moving around +/- 5MPG despite maintaining a steady speed and throttle. I'm thinking Lambda sensor - or Vacuum leak.

[doodlebug]

Climate control pump switching in and out? Turn aircon off and if it still surges, you're probably right.

HTH

[Paul Drawmer]

Try the bellows hose upstream of the mass air flow meter. Look all round it for cracks which will be letting air in intermittently.

Also - if you happen to have a non-original type of paper filter; ie a cloth of foam jobbie - sometimes if they are over-oiled, you can get a deposit of oil on the wire sensor in the air meter, wash it off carefully with a soft brush dipped in alcohol or brake cleaner or anything really volatile.

[eliot]

Definatley not the air con, And it has a proper filter. Will check the bellows tommorow.