I have a toyota 4runner that has a problem starting. I sprayed starting fluid in the throttle body and it would start and continue to run. Now it will start and will not stay running. Does this mean I need a new fuel pump or fuel filter ?

The EFI relay also powers the engine ECU. Try a new relay.

If it has known good spark and fuel pressure try spraying carb cleaner in the throttle body while cranking engine to see if it will crank.

Could be clogged throttle. Get a throttle spray and clean the the throttle body and the jets.

Likely a fuel delivery problem.

Check the filter, as it may be clogged and due for replacement. To test for fuel delivery, open your airbox and spray some starter fluid (purified ether, usually) down into the throttle body while someone else cranks the engine. If it fires up and runs for a few seconds but won't run without spraying the starter fluid, then you know you've got spark and compression. If that's the case, there could be any number of potential issues: throttle position sensor (not very common, but it does happen), fuel injectors clogged (common if you use low-grade fuel), fuel filter/strainer clogged (filters should be replaced every 30k miles or so, on average), fuel pump failure (you should hear a buzzing from the fuel pump when you crank the engine).

If the starter fluid doesn't help, then the problem is no spark. Check each plug/cable for fouling.

Not a great idea if you haven't done this before. You can start a fire, or even ruin your engine. However, in general, remove the air cleaner and spray starter fluid into carb (or throttle body) about one second (one Mississippi) and try to start. If it starts and continues to run, rock on. If it runs a few seconds and dies, you have ither issue and are not getting fuel delivery. Seek help!

Was it running before you replaced the timing belt ?
Did you verify the timing marks are in the right place after installing the belt ?
Does the engine have normal compression ?
Will it try to start if you spray starting fluid into the throttle body ?

could need tuneup and may want to replace fuel filter....Thing i would do first....i hate starter fluid...really ******* rings in motor.....

If you think its fuel, spray some starter fluid inthe throttle body. If it fires up, you have a fuel problem, otherwise, check your spark plug wires, distributor cap and rotor. Also, check your fuses.

Spray starter fluid in the throttle body, turn it over to run. If it starts up and cuts off, you have a clogged filter or fuel pump bad. open the gas cap and have someone turn on (not over to run) and listen at the gas neck for a pump to turn on. I would change the fuel filter first, and go from their.

Spray some starting fluid into the throttle body. If the ignition system is working properly the car will start and run. While it's running spray more starting fluid into the throttle body little by little and see if you can keep it running. If it does run and stays running this way, your fuel pump is not working properly any more.