(G) Punto Eratic Idle

Hi,

I'm new to this forum, not sure if I've got the right section or not.

When I start my Mk 1 S60, it idles for a few seconds then the idle drops and sounds a bit chuggy.

Any ideas on what could be causing this.

I've just replaced the cat and oxygen as my CAT broke up and choked my exhaust.

I've also replaced all the plugs and leads as part of my service.

does it misfire if you try set off straight away and has your coolant level dropped

sounds like the early stages of head gasket failure to me does it start normally when warm

When I first got the car about 2 months ago there was hardly any coolant in it. I topped it up but it was losing water. I couldn't trace the leak to any of the pipes or radiator but a bottle of RAD weld seems to have stopped it.

Car starts and drives fine, just the idle speed seems to dip for 3-5 seconds then come up again and repeat the cycle.

I can't find a vacuum leak and have just replaced, plugs leads O2 sensor and cat.

Only thing I can think of are the idle stepper control of head gasket blowing.

Idle control valve?

or is it ECU controlled

I would be inclined to try the head gasket if it's had a history of loosing water also rad weld is crap never use it or anything like it