Check engine soon lamp (emissions) keeps coming on then going off after a couple of days, theres no difference in performance of the engine and it seems to occur whilst sitting in heavy traffic or a jam whilst on idle, thought it may be crap petrol but its happend on 99ron as well. Do any retail parts outlets do free diagnosis (like they do in the states) in the UK? Whats causing this and whats the likely cost?

First check, the petrol cap is properly installed,check it also for any visible demage.

First check, the petrol cap is properly installed,check it also for any visible demage.

Petrol cap checks out OK, no damage and vent holes clear. thanks

My local mechanic does not have the equipment to download the fault codes from the management unit (Does anybody know of somebody in Suffolk UK that could do this cheap and advise what is required) He thinks its not too important as its not affecting anything (at the moment)
A friend with a similar car / fault took his to a BMW dealer and ended up with a bill for £400 for a sensor? OUCH!

Any more ideas much appreciated

cheers
D C

Petrol cap checks out OK, no damage and vent holes clear. thanks

My local mechanic does not have the equipment to download the fault codes from the management unit (Does anybody know of somebody in Suffolk UK that could do this cheap and advise what is required) He thinks its not too important as its not affecting anything (at the moment)
A friend with a similar car / fault took his to a BMW dealer and ended up with a bill for £400 for a sensor? OUCH!

Any more ideas much appreciated

cheers
D C
Because your car is only 4 years old ,I do not think it could be for instance oxygen sensor, even symptoms indicate so(light on/off), how many kilometers did you make on this car? Next thing , you could check the rubber boots on spark plugs and cables for any cracks and proper fitment, sometime simply think like that can cause the problem. It could be also camshaft positioning sensor, easy to replace and often failing on these cars, but again without scanning we can only guess!
Why do not you order scanning tool from States , is not expensive (around $140 US) and is good to have it.
http://www.bimmerzone.com/resettool.htm

Scan. Any component can fail at any mileage.

Hi dave, Hope you resolved your problem.
I have a 2000 323i and just the other day my service engine soon came on, like you it went off, a day later it lit up again. At first i thaught it was a coil misfire(happens often) i ussualy replace the coils. I had the car diagnosed and a DTC P1397 (BMW Code) was found. The mechanic told me a camshaft sensor needs to be replaced. Again a high failure BMW Part and is going around 80$. Hope this helps.

Update
Have found Garage in Ipswich to download fault - Air Mass sensor out of limit, they wanted £325.00 to replace it...... a quick look on the net and gsfcarparts.com have sensor for £50.00..... 5 min fit and all is OK now,just have to see if it holds up.