wh 5.7 running bad please help HELP! help!

[jtn]

the problem ?

sometimes the engine runs rough on start up.

random misfiring and stalling and very low idol

I have taken the car to the holden dealership and there is no fault codes relevant other than lean fuel code. with the car running duel fuel lp/petrol
that coad will pop up as soon as it switches to gas this is normal and the misfiring problem was there previous to the liquid icom gas injection installation.

most of the time the car runs very well and smooth the problem happens about every 2 months and can last for 1 day to 1 week it can start hapening in transit but mostly on start up and not always on start up.

PLEASE HELP BEFORE THIS STATESMAN SENDS ME MAD OR BROKE OR BOTH !!!!!!!

[Munz]

I'd start with replacing Spark plugs, leads then have the coils tested