Had our Broom Yellow Sporting Sei for 3 years now and reluctantly about to move on to something else however last week it started to misfire. Took it to shop and they replaced the spark plugs and wires which were pretty manky (although same shop had serviced it only a month or so earlier so replaced the plugs and filters) but it didn't fix the problem.

I've noticed that the coolant levels are dropping far quicker than they should be (filled it to Max about two/three days ago and it was below Min yesterday evening) and from reading other posts on this forum am now worried the cylinder head might be a problem. Will take it back to shop but in the meantime what should I look for to help me diagnose the problem?

Since we are selling of px-ing it soonly I don't want to have to pour money into the wee thing but if something like that needs done, there's no getting away from it...

if its running poorly and losing coolant but not leaking then the head gasket is a definate possibility.