Car seems to be lacking a bit of power when floored, and occasionally there is a sort clattery noise which sounds like its from the top of the engine. (For example, coming off a roundabout, say 30/40 mph in second, floor it and you get the above scenario) It's had new plugs, leads, dizzy cap, rotor arm. But the original plugs look exceptionally clean, very very light brown, so it does look as though its running very lean! It's an EU2 supersport, with the original Rover sealed ECU, so I gather theres nothing can be done with this. If it is fuelling, is there anything else to look for, maybe sensor etc, that could cause lean mixture? I disconnected the Lambda sensor, but this didn't seem to make any difference on the road whatsoever. So does anyone know if anything else controls fuelling/mixture? Also, theres a vacuum pipe from the plenum which goes to the ECU via a small black oblong box mounted on the bulkhead. Does anyone know what this box does? It's not misfiring or anything like that, all temps are normal. it's also had a new fuel filter, and the fuel pump primes as normal, but I think if there was a problem with the fuel pump, it'd be more noticable/serious. Bit baffled at the moment! Anyone experienced something similar? Oz...