corsa 1.4 r reg cylinder head gasket

[k10s23]

I DONT KNOW ANYTHING ABOUT CARS SO ANY ADVICE WOULD BE APPRECIATED ,Corsa would not run properley for a couple of weeks it would run smooth for x amount of hours or even days then run as misfiring for x amount of hours or days.Just had AA out and this is his wording on report sheet misfire on 2 + 3 cylinder with no compression suspect cylinder head gasket leaking .AA says this could cost me �250-300 ,for the record ive had no water ,oil leaks or smoke from back ,just phoned mobile repair man as the car will now not run and is stuck on drive and repeated the AA diagnosise and hes quoted �120(seems too cheap obviously) as other people have told me valves have to be skimmed ETC thanks for any advice

[xud]

It sounds to me like the car has not been serviced for a while. Before spending hundreds change the plugs, oil and filter and give a good run down the motorway to blow off a few cobwebs.
Failing that it could be head gasket gone, but id you're not losing any coolant you should investigate further - maybe injection/ECU problem
It is not the valves that are skimmed, it's the cylinder head.
For a new gasket and head skimmed I would charge you around �200, and it would probably take the best part of a days work plus the time to get head skimmed. If your valves need re-grinding it's therefore going to cost more.
It just goes on and on - believe me.
I'm not a cowboy and wouldn't rip you off, but things cost too much nowadays and besides, I wouldn't want you to come back to me in a few weeks with the same problem again, if you know what I mean.
My advise would be to fix the problem and get rid of it and buy a diesel. They might be noisy, smokey and slow but properly maintained they will outlive any petrol car.