came off a dual carrige way last night and as I came off the round about into the village the engine started to click badly and I lost power, power is fine upto 30mph, but the goes after that and the car sounds like a scooby under any acceleration (eg pulling away) and there is a high pitched screech. its a cvh efi, any ideas? limped it home and it will start, but dunno what it is, oil is fie, no bits in it, nice colour temperature never went above normal,

any suggestions? only need it to last another month or so, or am I going to need a new engine?