TB42 EFI Dual Fuel problems in fuel

[ati289]

G’Day friends
My injected TB42 has problems starting and idling on petrol. It was always starting easier on gas, the previous owner said it would be normal. But since a week I am experiencing heavier issues. To start it I need to crank really long and/or more than a couple of times until it fires. Very often it needs a few cycles to rev up to 900 rpm. After starting the idling rev is very low when the engine is cold. As soon as you turn on the aircon the engine starts to stall, it kind of fights to keep running until it dies after almost a minute. If you would prevent that by manually accelerating you might get one or another knock until the RPM needle passes the 1000rpm point.
Same way of dying when I go in D or R
Idling problem is gone when warmed up.
These Problems occur ONLY ON PETROL.
It starts and runs perfectly on LPG.

Information to the car: TB42 EFI with ~ 250k in a ~350k Body
Ignition wires and spark plugs 5000k old
Fuel filter 5000k old
Don’t know whAt other relevant information you need to help me, I will answer as soon as possible.

Your help will be very much appreciated!
Cheers Atilla