Does anyone know if 98 outback tps can be used in a 93 impreza?

If the connectors are identical then that's a good sign it'll work.

 

Is the 93 impreza an EJ18 or EJ22?
98 Outback an Impreza (EJ22) or Legacy (EJ25)?

 

Look up a 98 and/or 93 TPS on ebay, amazon, google, subarus opposed forces website, www.car-part.com and you can find out fairly quickly if they interchange.  that may verify they're the same, but even if you strike out there, they still may be interchangeable.

 

I would guess they're different.  Phase II transmissions I think started in 98 and they went to OBDII between 93 and 98.  

 

If you're 93 impreza is an EJ18, much is substantially different from other EJ intake manifolds too and I wouldn't guess the 98 would work.

 

Unsure if it matters but a 98 Outback impreza would be EJ22, Outback legacy would be EJ25.

I'm going to say not likely, all of the obd1, 90-94 ej subarus I've ran across have had a 4 pin tps, the 95+ obd2 cars are 3 pin. Granted my impreza experience is very low but the parts are basically identical on ej22s, the ej18 probably isn't any different.