My 207, since about a year, is having some troubles 'passing' to LPG. It starts regularly on petrol then, as soon as the ECU switches to LPG, if I'm not pushing on the gas, it shuts down. My work-around is to 'manually' go on petrol mode and switch LPG on as soon as the thermometer starts moving. What can be wrong? I add that few weeks ago I got a 'misfire' error. But after few hundreds km the error light went off.
Spark-plugs changed about 20000 km ago
UPDATE:
I brought my car to the gas-specialist, he found a leaking lung, after replacement my car started to work properly again.
He told me the leakage was directed to the manifold enriching the carburetion too much causing engine problems on startup. This fix also improved my car's autonomy.