Civic overheated...

My wifes 92 Civic Vti (jap model, 1.5 sohc vtec) overheated. I fixed the problem (thermostat) but now when it warms up the idle starts pulsating. It revs, lets off, revs, lets off, and does this cycle about once every couple of seconds. Can anyone tell me what's broken??

vacuum hoses leak? or intake not securely sealed.

Sounds like some kind of problem with the IACV did you bleed the air out of the cooling system? That can cause a air pocket tpo go into the IACV and trick the ecu into thinking that the motor has not warmed up yet and it will do the same thing you are describing. If you did not blled the air then i would try this before doing anything else.

I didn't know that. I'll look for a place to bleed it as soon as I get off work. Then I'll reset the ECU and see what happens. Thanks a lot for the info.

My wifes 92 Civic Vti (jap model, 1.5 sohc vtec) overheated. I fixed the problem (thermostat) but now when it warms up the idle starts pulsating. It revs, lets off, revs, lets off, and does this cycle about once every couple of seconds. Can anyone tell me what's broken??
i had that problem with my 95 honda civic. you need to check the coolant level and fill the coolant up because you don't have enough coolant in the radiantor and after you do this it should be fine.

Hey thanks for the help, I've got it fixed now. I had been putting coolant in the reservoir but eventually decided to add it to the radiator and the level in the radiator was quite low. I reset the ECU just for good measure, then warmed up the engine and once I eventually found the bleeder, I bled it. Now it works like a charm. Hondas are a little different, I've never seen a car that used the upper radiator hose as the exit side from the engine. Anyway, thanks a lot for your help. However I already had my eye on a Prelude just in case the head gasket was blown (a used car is cheaper than a head gasket in Japan.)