. My 1.6i cabbie won't start very well and is running rough, I had an oil leak and discovered that the oil was extremely thinned down with petrol, suffering from some kind of fuelling issue, it must have found a leak being too thin as I've changed the oil and the leak stopped, has anyone experienced anything like this please and can help at all?

 

i think the only way the fuel could get into the oil is if it's massively over-fueling. You need to get it set up right as it will do damage to your bores and bearings

 

There's a lot of reasons. Overfueling because of wrong set up, worn gaskets etc. inside the fuel distributor, worn and leaking injectors.

Plus worn piston rings are also a reason for fuel in the oil.