Celica high fuel consumption and stalling

Sounds like a possible MAF issue. Has the car's performance declined, like feeling sluggish when accelerating? Have you checked the MAF sensor connector for damage or loose connections?

Yes, the car feels less responsive. Is the connector easily accessible, and could cleaning potentially resolve it?

The connector is usually accessible, but cleaning might only be temporary. Given the symptoms, especially the increased fuel consumption and stalling, it's likely the MAF is defective. Getting it diagnosed and replaced at a workshop is best to avoid further damage.

Took it to a mechanic, and the MAF was indeed defective, as suspected. Repair cost was 365€.