"GT" > wrote in message
b.com...
> "Catman" > wrote in message
> ...
>> On 20/01/2011 12:13, GT wrote:
>>> 156 2002, 2.0 JTS petrol. I (the car)had a splutter/cough a year or so
>>> ago
>>> and it eventually went away on its own. Its come back now and I would
>>> like
>>> to at least figure out what is causing it, if not fix it. The problem:
>>>
>>> Its independent of gear (done it in 3rd, 4th 5th). I don't tend to rev
>>> over
>>> about 4000 most of the time as its a nice torquey engine. Problem occurs
>>> under load, usually at around 2000 revs. It is repeatable - the 270
>>> degree
>>> slip road onto the M8 at the top of Livingston is about a 50mph corner,
>>> 5th
>>> gear. As I come out of it I speed up to er... 70 (ho humm!) and it will
>>> splutter most times there. It also does it in 3rd coming out of the
>>> silly
>>> little roundabouts they stick along in-town dual carriageway 40mph
>>> stretches. Its a cough/splutter, lack of power, followed by 'beep beep'
>>> motor control failure - go to dealer. As I feel the splutter starting,
>>> if I
>>> back off on the accellerator and just speed up more gradually all is
>>> well.
>>> If I drop a cog and increase the revs, all is fine.
>>>
>>> I have ruled out dirty fuel as its been through several fill ups.
>>> I have rules out engine temperature as it doesn't make any difference.
>>> I have ruled out spark plugs and electrics because the revs are low, so
>>> the
>>> demand is not so much - wouldn't this cause problems at higher revs when
>>> there are more sparks per minute?
>>
>> *maybe*
>
> I got a cable and diag software. I found 2 fault codes: P0300 - "Misfires
> detected (generic) and P0303 - "Cylinder 3 ifnition failures".
>
> "The emissions Monitoring system has detected misfires, an Air/Fuel
> micture problem or other indicators of emissions exceeding the permissible
> level. Check the plugs, ignition and fuel systems, and the ending
> mechanical condition, and that the oild level is not too high, or oil
> change overdue. Defects contribute also to O2 sensor degradeation and
> premature catalytic converter efficiency loss.
>
> The reason for this fault is that the EDU has received very high signal
> from the sensor. The fault is not is not detected now, but it is stored in
> memory. Clear fault codes, and observe for future appearance of the same
> fault. Dashboard warning light was activated for this fault."
>
> Sounds like the spark plug or wiring is failing on cylinder 3. I checked
> out the throttle sensor and whatever I did to the pedal, the software
> reported a valid position - I couldn't get the graph to flicker or jump at
> all.
>
> Any thoughts to add?

Still not done anything about this yet, but another point to report that
might point to something specific: I've been experimenting over the last few
days and it appears to behave perfectly (faster) when the engine is cold -
only starts to splutter under heavy engine load and after the temp guage
starts to move - maybe over 60deg.