This is a low-ish mileage car (48,000) but has an LPG conversion (aftermarket I believe).
On a cold start the engine runs well initially but as it starts to warm develops a lumpy idle that sounds like it is mainly multiple cylinder but with the tendency towards one more than the others (if you understand what I mean) a sort of soft misfire which does not sound like a coil pack. When hot the engine has a tendency to stall at idle.
There are no codes in memory.
Compressions are about 200psi in five strokes on 2, 3 and 4 but no1 takes longer to rise being about 175psi in five strokes, although it does rise to the same pressure it takes longer.
I intend to smoke test for air leaks and maybe it will show up any valving issues.
Idle manifold pressure is poor at 550mbar.
4-gas shows lambda is high at about 1.04, HCs and CO are very low, O2 is about 0.8% and CO2 is 13.2% so I would think EGR is working ok.
Pre-cat lambda sensor is switching but the ratio is also tending towards lean.
My thoughts are that the LPG has killed the valves.
Recent oil change and genuine Ford oil.
The strange thing is the high lambda when I would have expected it to be running rich with the poor vacuum readings.
All the above running on petrol, not even bothering with the gas at the moment.
Any ideas?
Shaun