M50 Problems, misfire

[hash]

Hi, Hopefully somebody can give me an idea of where to look next,
First the car started to misfire a little not all the time, and under load in lower revs and a little at the top end but loss often.

First i cheched all plugs, which were badly worn so, cleaned them up for the nxt day and did seem to help, but now since fitting new plugs (same ones) it seems to of got worse, misfireing and what seems like a preignition.

Have tested coils and cleaned contacts, All read the same resistance between outer pins.
Have since tried it running with o2 and maf unpluged at seperate times with no change other than poor idle.

other symptom which was there before is its flat as a dodo, which i put down to the vanos being buggered.

Any help appreciated, have also looked over for split pipes but couldnt find any.

[hash]

Is there a resistance it should measure or how do I test it? Cheers

[StefanAnghel]

I've also heard of labda getting wet causing missfire

[hash]

Anybody no how to test the cps? Other than swapping it for a good one?

[Cook318IS]

Anybody no how to test the cps? Other than swapping it for a good one?

The bentley manual says it should have a coil resistance of 1280 ohms ± 10% between pins 1 +2 on the crank sensor.

[wullie325i]

check the lambda probe as well

[E30BeemerLad]

After checking the cam sensor and the crank sensor and the lambda, also check the rail that the injectors are connected to for the electrical connections is pushed down properly and good contact is being made for each injector socket.

[Brianmoooore]

M50 ignition coils are a known weak point. Can't tell from here if it's 'that' kind of misfire, but getting hold of a couple of known good coils and swapping them in would be high on my list of actions.