For me, no problems whatsoever with the Greenfuel SGI kit installed on my 2002 Camry 2.2L A/T. I used to manually switch to LPG after a couple of minutes everytime I start the engine and manually switch back to gasoline before shutting the engine off. This was the crude workaround I was using to prevent that mysterious and intermitent engine stalls at times when auto-switching from petrol to LPG.

Went to Greenfuel >2 months ago to have it checked and if I'm not mistaken, they just made some adjustments with the vaporizer screw. Since then, my LPG has been flawless...(touch-wood)

Cheers!