goes up and down at idle...

I just finally got a new timing belt put on and got my timing fixed right...now at idle my car RPM's goes from 800 to 1200 back down to 800 constantly...check the main vacums make sure not a leak and still cant figure this one out...i know i need a new o2 sensor but i gurrantee that aint the problem...any ever have this problem or knows what it could be please respond thanks....

try bleeding your coolant...on a zc the bleeder screw is on the back of the head on the thermostat housing.

that would cause my idle to go up and down?

How long was your car sitting without being started? Same thing happened to me. I put some Lucas fuel cleaner in my tank and hasn't happened since.

try to make sure u got all ur vacume lines in stalled in the right place

air in your cooling system will cause surging till its all aired out

air in your cooling system will cause surging till its all aired out

If bleeding the cooling system doesn't fix it, it will be the infamous idle air control valve most likely. :crying:

it could be the fitv.

heres the list i would go over step by step

1. bleed air out of cooling system
2. check all vacuum hoses for leaks
3. take off iacv and clean the little screen
4. take off fitv cap and screw in the center piece

If bleeding the cooling system doesn't fix it, it will be the infamous idle air control valve most likely. :crying:
Do you bleed the coolent when the motor is hot and running? Jags