Peugeot 307 xr 2004 not eating gas

The vehicle cuts off the gas while driving - it doesn't eat and the speed drops slowly but doesn't stop,

Once the ignition is turned off and on, it recovers. Very rarely, it drops below a thousand rpm and stops at idle

- I made the coil, spark plugs, the trigger, I made the top cover, I installed the throttle valve

- We disconnected the LPG connection, only the gasoline is connected

The same problem still continues

especially in stop and start

When we look at the brain, there is only a catalyst failure

Is there anyone who can help with this, I would be very happy if there is a good master in Izmir or someone who has been through it before, I would appreciate it

Thanks for your answers in advance.