[volvolvo]

I bought this Bi-Fuel V70 several years ago from Crew and after a lot of LPG hassles worked out I needed a new stepper motor about £340 in 2016. I have fitted it and had pretty good running. However I have been getting yellow engine warning lately which with my brilliant commercial Autel tool (MaxiDAS DS708 £500 second hand) it brings up error code 3502 on the Engine ECM misfire on cylinders 1 and 5. When I run the live diagnostics you can see the misfire count climb running under LPG but switching over to petrol there are very few if any misfires.
The problem is exacerabted by this cold weather and when the engine is warm the misfires tend to settle down but on idle in cold weather it can often throw up the Yellow engine fault and subsequent Misfire diagnostic which will clear on erasing the code. The engine can be days or weeks without a misfire then all of a sudden as this morning took a while to reset clear and reset. So my thoughts are that it might be
1 plug coils on cyl 1 and 5 but have swapped with no effect
2 possible air leak on hoses but have checked and they look ok
3 LPG filter has passed dirt to the Stepper piston that has very critical clearence with the body since when warm the misfires as the slightly lumpy running dissappears and misfires much reduced or absent but have changed filter
4 in the warmer summer weather dont seem to have these problems
5 One peculiar point is when I park the car on grass say at a steam rally it became very sluggish on LPG as if fuel starvation but on switching to petrol all was ok so is this a condensation problem in the stepper motor due to contaminated LPG
6 Sadly Shell have stopped selling LPG so obtaining it from a good source is more difficult. ASDA still sell it at Queensferry but they think they might stop so with fewe people using LPG (or even know what it is ie a valuable intermediate fuel till we all go to Hydrogen!.... LOL)
7 so will fill up from a different source near Chester and see if it helps as I filled up from Morrisons in Wrexam and had loads of misfire problems from their LPG so suspec the tanks are not regularly cleaned out?
8 Anyone with a similar problem let me know and how you cured it.
9 I am also after a new set of the 5 rubber hoses that go from the stepper body to the cylinder head anyone got any for sale?
10 someone mentioned turning the delivery pressure up presumably via the pressure vapouriser and on my factory fitted one it has the single hex bolt in the middle but seems to make little difference but only turning slightly and marking it so it can be returned to original setting. Anyone know how to set this easily with a guage?

TTFN

Kevin