Okai, ive got a 4 cyl TR EFI runs on petrol/lpg

It use to idle rough on lpg, like it was just bout to stall then kicks back in, on petrol it idles fine.

So i played with that twist knob on the gas line between the engine and the firewall and opended it up all the way, the thing idle PERFECT and sat at bout 700 instead of 500 and it went HARDER and smoother on gas then it did on petrol lol
I thought this couldnt be good for fuel economy and just as i thought, i ended up doing something round 25L/100 ks haha

So i twisted it back down to just when it gives an okai idle/slight rough but it still eats bout 15l/100k on gas.
I think 15L is normal considering for petrol its prob round 13L so an extra 2 L to the 100 for lpg isnt bad i think, but i dont know ****.

My question is, how do you increase idle without having to change the fuel ratio. Because if i could get it to idle a bit higher on lpg it wouldnt be running so rough (i hope)

most lpg systems have an adjustment on the hose from the convertor to the mixer this should be set while holding the rpm up to 4000 wind it in untill motor revs drop then back out untill its at the point where its not changing the rpm then go aprox 1/2 turn out fron that point.........................the other adjustment is on the convertor this is a idle mixture screw in is lean out is rich in most systems keep turning this one untill it runs smooth at idle