Just got the car back after new head gasket etc but still having problems. Car does not always fire up first time, will start but then cut out. It does start second time ok but idles rough for about 10 seconds then is ok. Once going everything seems fine but the car has cut out a few times, it doesnt just die but the revs start to vary between about 300 -1200 rpm and the car wont pull away properly. I turn the car off and it wont start again for about 5 minutes, it turns over but wont fire up, then all is fine again once it starts. I'm assuming its something electrical but was hoping someone could point me in the right direction as i'm getting a bit pissed off with it.