Explosive backfire that shatters the plastic inlet manifold! Owner started car after being idle for several days to be greeted by a very lound bang under the bonnet and the revs going sky high. I inspected the underbonnet and found the plastic inlet manifold has had large bits shattered out of it. I had a similar experience on a Citroen Xsara CVT which had a similar engine. Never really got to the bottom of it but maybe injectors leaked after shut down forming an explosive air fuel mix in the inlet manifold? I spoke to the dealer leading hand and he had one with similar problem on a 306 GTi6 and just cleaned the injectors without really being able to pin it down. Anyone had similar problems and more importantly why it happens and a fix if any. Thanks in advance.