[starman1955]

When cold my Megan scenic 1.4 16v run rough and lumpy but as the temperature raises the problem fades away and it runs smooth, I’m guessing this is a sensor fault but can anybody help with which one?

Regards Steve....

 

[bobbydog]

When cold my Megan scenic 1.4 16v run rough and lumpy but as the temperature raises the problem fades away and it runs smooth, I’m guessing this is a sensor fault but can anybody help with which one?

Regards Steve....

Hi and welcome Steve,

I'd start with the coolant temperature sensor.

They can be tested in situ with a multimeter.

 

[Zonked Plonker]

Hi, that is also a symptom of a dodgy coil, as the heat rises in the coil it expands and connects the bad continuity in the windings.

 

[madnoel10]

Ignition coils are more likely to break down when hot rather than cold. In this case things improve when the engines heats up.

As Bobbydog advises check the coolant temp sensor and its electrical connections.