VY hissing and issues with LPG

[mikevy]

Hey all, long time reader, first time poster.

Had my 2003 VY Ecotec V6 Dual fuel for about 2 years now, had a fix a few things (alternator, radiator), but I've run into an issue I'm not certain about.

Over the last couple of months I've been using it on LPG, but I've noticed whenever I idle or hang around low speeds (20kmh<) for more than 5 mins I'd get the check engine light pop up on my dash. After this happening a couple of times I just learnt to swap it to petrol whenever I was in heavy traffic.

I was driving home this evening on LPG and I came to a stop at a intersection, heard a loud bang come from the engine and the car died. I swapped it over to petrol and it tentatively started, then came back to normal. Got it home and tested it, runs terribly on LPG, shaking a bunch and dying when I give it any power. Also noticed a hissing noise coming from the engine when the car is on and more noticeably when I turn it off (even when using petrol). Engine is also rattling while idling currently (on petrol).

I've done some reading, it might be the PCV valve? Any suggestions are greatly appreciated.

 

[EYY]

Has it blown the maf sensor off the intake pipe, or split the intake pipe? The problem is an unmetered air supply caused by the backfire.

Usually a poorly maintained ignition system is to blame.

 

[mikevy]

Could be, I'll have a closer look when I get home this arvo