Bravo B2600

On LPG? If so.. check radiator water level.

Start with the fuel pump, or fuel pressure regulator. At a guess it is only just managing to keep up until you put "acceleration flow" demands on the system. It then slowly loses pressure until there is insufficient pressure to push fuel through the injectors.

If it was me I would going for the fuel filter/s first.

Mazda have had a habit over the years of every now and again building their vehicles with two (2) in line fuel filters .

The second one is usually hidden in some way out place like a wheel arch.

Guy who used to work with me had a 929 which for no obvious reason started doing weird things something like yours.

Finally pinned down to a second fuel filter in the rear wheel arch that nobody new about.

Black as when removed and slick as 'eel chit' when replaced with a nice new clean one.

Fuel pump/s are next . If the fuel is being delivered to the injector system Ok then maybe a electronic diagnosis is required.

Not good happening before X-mas , however all the best to you and yours.

Are you sure it's a fuel issue?
I've had similar symtomps with a petrol motor, the problem was electrical,once it ran for awhile it got hot then failed after about 15mins

Senbloodysational..............It be going...........
Changed out the fuel pump and strainer, the motor is running much better than it has for a while.......must have been on the way out for a while or the strainer wasn't letting much fuel through. (looked like it had been sitting in a cup of tea for a few years).
Again thanks for the guidance a few questions on here saved me many days of frustration.

Cheers