My cougar has recently failed the mot on a couple of bits of welding (which I knew about, and can repair) but this time it has also failed on : exhaust lamba reading after 2nd fast idle, the car had been stood for approx 2 months, and has never had this fail on an mot previously, could it be that due to it standing for so long this may have caused the problem? If so what would be the recommended solution, any tips appreciated..