check the fuel pressure is in spec. Everytime I get this code it's out, get it back in and you'll be good.
I had clogged injector, dirty air horn/injector holder assy tar filled regulator - all fixed still wouldn't go away for longer than a few days. had the dealer come out and look at it they cleaned the stuff I did and ran a tas learn. next day code back.
i've already wasted lots of time with this, take my advice. A man named Jeremy helped me out on here so I'm here paying it forward. the lpg regulator has an adjustment under the tamper proof cover.