My Aussie 93 Maxima Ti runs on Petrol & LPG..when on LPG the car runs smoothly but when i switch her over to Pertol my car hesitates and shudders under acceleration.( Rough ). Any idea where to start...?

 

Maybe running too rich on the petrol. If it's not knocking, that eliminates lean conditions. I assume LPG has different injectors..could have petrol injector problems..seems an apparent fuel problem, so do power balance test, check fuel pressure, regulator.