1996 Toyota Avalon Recently Encountered Check Engine Light On Toyata Xl Code

i recently encountered check engine light on a 1996 toyata avalon xl. code p0104 came up. i replaced part # 90910-12080 with a used one to see if that would work. it worked for 90 miles 3 different times. i put the original one back in and it lasts around 15 miles each time before the check engine would come back on.the part is called the EGR VSV VACUUM SWITCH SOLENOID VALVE. would you suggest buying a new part or bring it to the dealer for further observation