My throttle body needs replacing on my bravo 80 but cannot find one anywhere, they is like a idle control valve on the back and been advised that you cant just replace that you need to replace the whole unit? Is this true?

I took the idle control valve off and put it back on and it revs the car up and down to about 3k down to 1 all the time, what should i do? i have just kept it off at the moment but i need to sort it out.