Hello,
First thank you everyone so far for your advise.
I didn't give you the whole picture when I said the car was stock. I missed out one important detail, the car has an LPG conversion (I do a lot of motorway driving so please forgive me)
After reading some of your posts I thought the first step would be a re-map. When it is running on petrol it is damn good, real happy. However on LPG under medium hard and hard throttle the engine feels like it is miss firing and causes the car to lurch. Also the engine light comes on if you don't back off the throttle but after a few seconds it goes off on its own.
I think I may be a fuel delivery problem. I have had all the coils replaced as the engine code reported a miss fire on 2 AND 4 cylinders and I was told this is a common fault for mark 1 1.8 20V engines. So this leaves me with air or fuel.
Can anyone offer me some advise as I do not want to have to remove the re-map as it rocks but having to change to petrol every time I want to have a burn is a pain in the arse.