Idle jumping up n down

[Chewy4000@aol.com]

My 89 200Tq, dicided to idle up and down between 1006 and 1008 rpms, at a
perfect beat.

I changed the valve. Everything good for a week, then back to the idle craze.

Know im told theres a relay under the dash called rpm stabalizer, the block
diagram said yes, but cant figure out wich relay it is.
Dealer whants something like 200$+ for this.

Has anyone had a problem like this or some kinda help here.

Thanks in Advance

Chewy
89 200Tq 197k
84 4000sq 115k