Hello Geoff,

Sorry to hear about your issues. My wife had the same issue on her 07 plate 9n Polo. Her engine code was BBM. Is your 54 plate a BMD? We ended up calling the EML the £500 light as that was how much it cost to rectify the problem at th dealer.

The issue is going to be one of 3 things; compression, timing or fuel/air mixture. The older BMD engine were prone to issues with the valve seats leading to compression problems. What the dealer don't tell you when you buy this motor is that they prefer higher octane petrol and not you run of the mill supermarket fuel. The other thing is ensuring that the engine has had the oil services done bang on the dot with the recommended grade of synthetic oil.

I agree that the fault code should be read with the VCDS system. I would not be too quick to condemn the O2 sensor as these are usually bullet proof. It's worth testing the pre cat sensor if you have a Volt meter to see what reading it's giving and determine the voltage negative/positive readings refer to whether the engine is running lean or rich.

The issue with my wife's car was a failing fuel pump but the garage has wrongly diagnosed a faulty cam position sensor hence the inflated price. Parts darts can be a very expensive game to play.

If your car is running smoothly it's unlikely to be a compression problem related to worn valve seats as in those cases the car runs and sounds terrible. In addition there is no repair for the Valve seat issue Volkswagen UK recommend a replacement head as opposed to relapping. Unless you can extract some kind of goodwill payment it will require you to sell your first born child, lol. But don't jump the gun it might be something minor.

Volswagenforums.co.uk is also an invaluable source of good advice.

Thanks Guys for the time taken to submit your replies,

I have had the codes read again and number 3 cylinder misfire is recorded as too is the O2 post cat sensor showing as intermittent, I have spoken to relieable garage locally and he says pretty much the same thing regarding possible faults and the most most expensive is of course the main suspect head cylinder vales, however with the mis fire the is exception that when he took it out for a run there was no juddering or tick over issues it ran nice and smooth so on return he added a bottle of Wynns hydralic valve lifter to the oil and said if it was going to do anything it would be within the next twenty miles or so and sure enough EML when out and only comes back on now and again. He said if this was the case then it could be sticky valves from the incorrect oil at service intervals, he also said he would be reluctant to fit new lamda sensors at this stage.

I have arranged for it to have a service ready for the MOT and I shall add a second bottle of Wynns and see how that works but I'm not going down the exchange head route as the car is not worth the money being spent on it quoted upwards of £900. I think as the engine runs smooth I'll either sell to a private buyer making known the EML issue is related to possible valve issue or offer it for part exchange as part of the deposit to the next car ( not a Polo ).

your thoughts as always appreciated.

Geoff

VAG Error Code: 16687
EOBD II Error Code: P0303

Fault Location:
Cylinder 3 - Misfire Detected

Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Lack/loss of power.
Hard start.
Engine hesitation.

Wiring/Connector(s).
Ignition system.
Fuel injectors.
Fuel pressure.
Running out of fuel.
EVAP canister purge valve.
Evaporative emission system.
Low compression.
Base engine problems.
Engine Control Module (ECM).

Special Notes:
This feature search for engine misfire in a specific cylinder. Most of the time the cause for a misfire is a lack of combustion in a cylinder due to absence of spark, poor fuel metering, or poor compression.

Tech Notes:
The P0303 code means that the cylinder 3 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 3. If the problem persist more tests needs to be done to diagnose problem.

When is the code detected?:
Engine Cylinder 3 is misfiring.

Description:
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

As taken from my EOBD II Fault Codes Software

Well so far, I don't believe the Wynns did anything but for £5 worth a shot however with half a tank of petrol I shot a full bottle of REDEX in and the light has now gone out coincidence or did it clear something I don't know.

I'm hoping that as the engine runs fine light on or off that maybe it's something as simple as sooty deposits on the valves ect but we are going to only fill it with top grade fuel rather than the supermarket offerings from here on in. Its due it's MOT later this month so I'm providing the correct grade oil and plugs for the garage to also do a service at the same time.

I have now one other problem to resolve it's the passenger seat flip forward to let others in the back, it feels like the plastic connector has come out or snapped of the seat frame under the upholstery, I can get my hand up inside to can grab hold of the palstic block and push it back into its clip position but it pops back out it feels like a cable tie could be used to hold it in place but I need the back upholstery lifted to see what I'm doing so any ideas please.

Geoff

This is quite a common problem on VW seats. If you can't be bothered to fix it you can reach in and lift up the centre catch by hand while lifting the seat in the normal way. However some garages will fail the MOT for this as a safety issue. To fix it properly...

The seat has 2 cables from the handle; a long one to the catch on the handbrake side and a short one that goes straight down to the catch on the door side. The 2 catches operate independantly so you can see which cable you need from which catch doesn't work. The long one goes diagonally across the back of the seat and is a bit stressed so this will usually be the broken one.

German and Swedish do the cable for about £5 (and these also have a nylon coating to reduce friction). To fit it you have to partly remove the upper seat cover. Sitting on the rear seat tilt the front seat forward and locate a line of metal spikes along the bottom edge of the seat back. Using a thin pair of pliers straighten these out (warning - they're sharp!) and pull the cover (front and back) down and off the spikes. You then need to push the cover up the seat back a bit until you can get to the inside of the seat lift handle.

Avoid disturbing the cover too much or it might end up a bit wrinkled when refitted. Remove old bits of cable and fit the new one (you'll see how they fit in to the handle/catches from the remaining short one). Note that the cable must be routed through the small plastic loops correctly or the 'pull' will be the wrong length - compare with the other seat and check it works the catch reliably before you put the cover back properly. To put the cover back stretch it over the spikes again, make sure everything is nice and smooth and then tap the spikes back over with a hammer (this should also help stretch the seat cover a bit more