OK - my ae92 SX rolla has developed a problem. After making a trip of about 30kms with 3 people in my car on the weekend I got out and noticed a hissing sound. On popping the bonnet I found that there was a tiny split in a hose running from the passenger side of the engine up to a control valvle on the firewall (heater hose I presume). Coolant was pissing out in a thin stream. Fair enough I thought - get another hose, replace it and everything will be tickety boo. Last night - after topping up the radiator (and overflow bottle) I took the car for a quick spin and the idle is now jumping all over the place. The car started fine but then began idleing up and down all over the place (between 800 and 2800rpm). There has always been plenty of water in the radiator and the temp gauge hasn't been in any dangerous territory so whats going on here? Any ideas?