i recently had to have my head gaskets replaced. they also did a valve job on it. well i got the car back and its been running good.until today. i was heading out on the freeway when the power of the car started to flicker on and off repeatedly. the car didnt stall though. i replaced the alternator and belt, let it run for ten minutes then started to drive it. its doing it again, and when i poped the hood to make sure the connections were ok, i noticed a little smoke on the passenger side in the back of the motor. i can also hear something that sounds like a boiling liquid. could it be they didnt seal it properly. i would appreciate some help

 

power as in electrical? If that is the case, electrical has nothing to do with the condition of the cylinder head gaskets. If its electrical, thats more of a charging issue.