1998 Toyota Camry fuel injectors or fuel pump

If you are not getting any error codes (check engine light), then measure fuel pressure with a mechanical gauge, If pressure is OK at fuel rail, check spark with an inexpensive tool you can buy at any parts store.

It sounds like a fuel pressure issue. If pressure and spark are OK, have the sensors scanned with a scan tool, looking for any out of normal range. The sensors should set an error code.

Another possibility is the CAT is partially clogged, you can have the backpressure checked at most garages.