Wonder if this newsgroup can help. I have a mate with an Astra 1.6 8 valve. It has been converted to run on lpg. This was done professionally. Though he reckons the problem is there when using petrol. The engine seems to be hunting and running a bit rough.He thinks it is one of the sensors on the management system. Occaisionally the engine amber light comes on but doesnt stay on. Any thoughts would be greatly appreciated together with any info on fault codes (website that gives code meanings would be ideal). I believe you can check the codes by plugging in a diagnostic tool available from Halfords.He said he would buy one as they are about the cost of Vauxhall diagnosing the problem in their workshops. Thanks in advance for any input. Howie.