Fabia 1.4 shuddering idle

[dragman]

Hy

Fabia 2001 year, 37406 miles driven, 1.4 8V engine AQW engine type.

When car stands still in neutral gear, engine randomly in time to time shudders which causes some vibrations which could be felt on steering wheel and gear handle. Shuddering is also visilbe on RPM gauge.

Shuddering disappeared for a while when we have replaced temperature sensor and when we have cleaned throttle body. But after a while shuddering appeared again.

Temperature sensor returns correct value (checked with vagcom).

Consumption is good, I could say below average, exhaust test values are in place.

Does anyone know why this shuddering appears?

[Ricko]

I think the idle is set a tad too low to help the emissions

[dragman]

Ricko can you please explain? I do not understand your answer.

[IanVW]

all 8valves jump on idle, old type push rod engines

[dragman]

IanVW in this case I assume shuddering would be present all the time. In this case is present randomly in time to time.

[Dmac1969]

I think I feel this happening occasionally on mine , although not to the extent that I'm bothered about it IIRC its classed as a 'characteristic' of this engine , ie 'they all do that guv'.

[Duggie]

Mine does this, it's nothing to worry about. The idle is set low. Idle = the speed of the engine when still and no accellerator applied (usually 8.5-900RPM). I quite like the judder, gives the impression there is actually some power on tap... all 68 rampant horses of it...

-Duggie.

[Ricko]

Hi dragman, Duggie explained what I meant ... to keep the fuel consumption low at idle, the idle revs are kept to about 850 rpm by the engine management computer. At those revs it nearly dies and the computer revs it up a bit to keep it going, hence the shudder. Maybe if the idle was a bit higher it would stay steady. But yes, the all do that, my missus' one does it too.