Petrol vapour through top of engine cover

[Jd1012]

Today my 2.0i E85 has had petrol vapour coming from the centre cap on the engine cover (not the oil cap). Does anyone know what could be wrong with it? Thanks in advance

 

[BumpyZ4]

Could be a leaky injector.

 

[markplant]

As above or fuel rail

 

[smorris_12]

Or a split fuel hose.

(Had that on my first car (Vauxhall Nova), was dripping onto the exhaust manifold resulting in little pops!)