I currently have the fuel injection system and air intake manifold removed, to carry out maintenance and repair. Whilst I have access to the coolant distribution pipe, it would make sense to test otherwise inaccessible components. 1. Firstly there is theThermal vacuum control valve. According to my books,at temperatures below 40 degrees, this allows vacuum to reach the control pressure regulator, and this seems to happen since there is effectively a 'circuit' between outlets D and 1 on the valve. This does not change when you subject the valve to 40 degrees, so I assume the valve is faulty. Also there is no flow between D and outlet 2 (to vacuum solenoid) at any temperature. 2. Lambda thermal switch. This should, I believe, have continuity at temperatures below 15 degrees (+/- 3degrees) and be open above that temperature. This seems to be working OK. 3. Idle speed thermistor. At temperatures below 15 degrees, the book says that the thermister signals the ECU module to switch the regulator to a wider open position. At any temperature this thermister appears to have no continuity between the two terminals on the thermistor. I assume that this is therefore faulty. Perhaps list members could let me have their observations on the above tests that I have caried out and also suggest any others that I should carry out on any other components whilst I have the opportunity. Graham (UK) vin 17152