98 toyota camry

Is it a 4 or 6 cyl? For a heavily computer-monitored engine like the Camry to lose significant power, would you'd think, cause the OBD system to register an alarm by illuminating the 'check engine' lamp on the instrument panel. This engine icon lights every time you switch the engine on just before starting.

Assuming the engine is not using coolant:

If the engine is not missing or operating roughly because one or more cylinders are not firing, then ignition timing (retarded grossly), blocked air-filter or exhaust can reduce an engine's power significantly.

If the engine is missing, then mixture issues especially lean can be caused by dirty injectors, fuel starvation: fuel-pump intermittant or its pick-up obstructed, fuel filter partially blocked Airleaks around the intake especialy below the throttle valve can be another cause. Mixture is controlled by the management computer via sensors detecting air-mass at the intake and oxygen in the exhaust. The engine will run with one or more sensors inoperative in an 'open loop mode' which may not be as efficient or power producing.

Intermittant ignition high-tension faults which show as rough running can be caused by electrical breakdown in the distributor cap or coil.

If the cam drive belt is a tooth or more out, reduced power can result. Some engines are more effected bythis than others.

The list is long, and these are assuming the engine internals are in good shape.

Jason

Have you tried replacing the fuel filter?