"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 have rules out air flow for the same reason - the engine isn't getting
>> through as much air as when the revs are higher.
>>
>> This (in my mind) leaves the knocc sensor, or something else.
>>
>> Any ideas / suggestions?
>>
>
> Is it drive by wire? If so, I'd bet on the throttle pot.
> Failing that I'd be giving the AFM a stern look.

Yup, I believe there is a small computer between my right foot and the
engine, instead of a cable!

I looked at the MAF (?) sensor in the air intake when I was replacing the
thermostat the other week. I had never seen a MAF before and was thoroughly
un-impressed!. I covered the top of the air intake with a cloth to avoid any
nasties getting in there, and it all looked clean as a whistle when I put
the hose back on. All has been fine for a few weeks since the thermostat
replacement, so I don't think its anything that I've introduced, but
obviously I can't say for sure!