Well, after a load of stress with lexia, I think I've finally found the problem. By all accounts, the wires are crossed in the 16 pin plug. Kwp2000 on early models requires both K and L lines, and it appears a wire that should be attached to one of them, is actually running to the engine speed sensor line, hence the rev counter moving up and down. Question is, how will I workout what to switch it with???. Any ideas?.