my 1990 Toyota corollas idle is revving up and down why? on 1990 Toyota Corolla

ive adjusted throttle cable as low as it will go still high idle and revs up and down

Asked by for the 1990 Toyota Corolla
Vacuum leak or faulty IAC and blown headgasket by now?
3 more answers , 4 more comments
Your Idle valve could be the issue
This may sound crazy but make sure it is FULL of coolant!! Check the radiator and FILL it up! If you need someone to check it out i can do it next week, i am just up the road! Post the results.
also heater is not working at all replaced thermostat still no heat.Coolant is full think heater core is clogged up also.would that affect idle?
The cooling system is not full, you stll have air in it. Let it run with the cap off until the radiator fan comes on. After it cools down check it again. If you need more info post a phone # and i will call, i am just up the road! How far are you from 40 West Food Fair?
ok thanks, will do let you no if it works/ did what you recommended coolant level dropped very slightly saw some air bubbles escape but not much. topped off radiator. what should I do next
change distributor cap, rotor specially high tension wire, maybe the wire its too old it may affect the distribution of current. It needs tune up
Did you guys ever find the answer out ??