happened to me once .. took me 5 mins to jack it up and push the catch open with a rod.. grease up the lock aswell because sometimes they dont lock properly so when driving loads let go so the bonnet flicks up and damages scuttle etc. .never happened to me in my rs turbo ownership but had happened to my mates when he had his. the misfire you have could be dizze coil,leads,plugs or need setting up.is it all standard~?