I have a 1985 For Xr3i.The Car start and i can drive it, but it continiously kills the nr 4 spark plug and when you smell the oil in the sump, you can smell petrol.The oil was changed x3 with petrol evident.Can this be cause by a leaking inlet valve?

 

is your oil level going up over a period of time?? i'd say you're piston rings are fucked and petrol is getting down into the sump.

 

Hi Clyde and welcome to the site

As said, sounds like you've got some proper piston ring issues going on. Done a compression test or cylinder leak test?

 

Hey, thank you guys.I will do a compression test on the cylinders and give you guys feedback regarding my findings.