Don't know if anyone can help but i've got a 04 reg Corsa 1.0 Life and when i turn the engine on it ticks loudly and has done for a while. But recently when i start it up and rev it, it dips unexpectedly and when i take my foot off the gas it makes a sort of scratching noise. Also it's undrivable because there's hardly any power at all. It revs normally but won't go anywhere. I can be doin 4500rpm in 2nd and it'll go no faster than about 20mph and it's sluggish, like when old cars didn't have the choke out far enough when they were cold. Hope that makes sense to someone, just wanted to try and get everything in! Hope someone can help me out!