1999 disco v8 runs badly on petrol, wellon LPG

Hi,
I've recently developed a problem with the v8 3.9l disco petrol/lpg conversion. it seems to run fine on LPG, but not on petrol.
It seems to start o.k. on petrol and sounds fine for a very short time, about 30 seconds. Then I hear misfiring, struggling and choking through acceleration, and particularly bad if going uphill. I can only drive on LPG, but I know I should warm up the engine on petrol each day. A non-specialist garage changed 2 oxygen sensors, but this hasn't helped.
Regards,
Richard (janul)

Sounds like your petrol pump could be on the way out. It runs all the time, even while on LPG, and if you ever run the tank dry of petrol, it can damage the pump.

I believe that is true for the D1 as well as the D2.

Peter

Airflow meter??

Is it single point or multi point LPG system??

fuel pump, injectors? surely its gotta be something just to do with the petrol fueling system if it works fine on LPG i reckon?

Thanks for the advice, I'll keep in mind the fuel pump, airflow meter, and injectors, before my next work, or visit to a garage. One other thing, I checked 3 of the plugs, the easier ones for me to get out, and they were sooty. Does this confirm anything already said?
Janul.

Airflow meter giving wrong indication to ECU making it run rich.

Are they wet and sooty of just plain sooty??

Run it on petrol for a bit then check them again, if there wet and sooty then its running too rich, I would have though on LPG it would just be sooty as its not a liquid in the cylinder, but I stand to be corrected (probably am wrong though).