My Patrol some mornings is extremely hard to Start and when it does only runs on about 4 cylinders for a couple of minutes.
Normally I start with no Pedal but when it plays up I have to depress the Accelerator fully . It then starts after quite a few attempts.
It then runs smoothly and will start first time for the rest of the Day.
The Car always starts on Petrol and switches to Gas after a couple of minutes.
It is like it is over fuelling if it fails to start first thing.

Hope you can understand my ramblings but before I take it to a Mechanic does anybody have any ideas ??