V50 p0172, still no fix.

[John Mawson]

Hi.
V50r
2.4i
2004
214,000km
Lpg added 2016

I've had the code p0172 since I owned the car for18 months now.

other codes include P0300, multiple misfire and P0137 o2 sensor voltage low (first time I saw that one)

Parts I have replaced.

Sparkplugs with 1 electrode
Air filter
MAF sensor
Lambda,2
Throttle Body, Oem.
Battery.

At first when I got the vehicle it had a hard job driving at low revs and giving throttle, like out of a roundabout, so I would have to shift down to alleviate misfiring, after changing the spark plugs it,s 80% better. Driving on Petrol is ls ways better. There was a period for about 5 months where I only used Petrol and no engine light came on.
I think the problems are associated with the LPG side of things.
I went to an LPG mechanic and he did something ? for 200 euros so
Idling on petrol or lpg is really steady now.
The engine lamp is still on. I use the Volvo every day and it seems to drive fine but one thing I now do is to turn the Lpg off until the engine temperature shows 90 as in cold weather the Lpg switches over to early and I get a warning to switch the Lpg off, so I wait a few more km before switching over.
I don't think I have a vacuum leak, I tried an improvised Smoke test and didn't see anything obvious.
I have a screen shot of the LTFT reading -23.4, so that's quit bad from what I have been reading STFT was 10.2%
engine speed 721
MAF 4.02
Time since engine start, 26 sec, which means its on petrol.
Fuel system 1 status CL which I think means closed.

I really don't know what to do, Mechanics don't like Lpg and Lpg mechanics don't really mess with engines.
I phoned a few Mechanic´s but they don´t have Volvo software.
If I found a Volvo Mechanic they'll probably charge me 300 euros to tell me to find an Lpg mechanic, that's my fear anyway.
Anyhow I hope someone has an idea about this.