i have a 96 NL 6 cyl Fairlane dual fuel
it runs fine on Gas ,, a little hard to start when cold ,, other than that Runs great on Gas

on petrol thats a different story ,, it will start eventually on petrol and will idle
it wont rev up freely ,, its like a flat spot ,,, you can coax it to rev sometimes but it has no power ,
i replaced the fuel pump , fuel filter and pressure regulator ,, no difference

then i replaced the MAP sensor = no difference
coil pack , ISC , Exhaust sensor , = No difference
pulled the injectors and cleaned them = No difference
PCV valve = No Difference

i had another ECU so i put that on ,, = No difference
temp sensor = no difference

i am running out of things to change and my patience is worn out as well
would there be anything in the BCM that would cause this ??
or 1 of the 2 sensors i havent changed
the Air Temp sensor ?? could this cause an engine not to run on petrol ??
i dont think the knock sensor would .

i have a reader and it says cam positioning sensor is out of range ,, but i have read that you can run the motor without it even connected .
and YES it has plenty of petrol in the tank

any help would be appreciated
thank you

Is this an NL or NF?

NL don't have a cam position sensor, hey have a dizzy.

Have you checked your fuel flow?

hahahahaha,, i have owned the car for 4 or so years and brought it as an NL ,,, i checked the id plate today ,,, and its an NF like you said ...lol

it has fuel going to the rail ,, i put a pressure gauge in place of the filter under the car and it had around 20 - 25 psi ... which i dont know if that is high enough ??
you can hear the pump working as soon as you turn on the key ..
and i checked the pulse at the injectors which seemed fine ,,, when you rev it the pulse increases

Id normally be looking at replacing the injectors - on LPG, they usually get baked-in gunk from fuel not flowing through and evaporating (especially if the fuel pump is switched off), and they end up blocked in places that injectors dont usually get blocked.

Have you checked your TPS? - theyre getting old.