I don't know the previous history of your headgasket issue, but I can offer some suggestions for the new issues. Regarding hearing coolant/air gurgling in the dash and heater hoses, the coolant is likely low. If the engine is missing/blowing sweet smelling exhaust, it could be another headgasket. The engine is NOT running rough, there's a chance there's an external leak (or the cooling system wasn't burped sufficiently to begin with). The up/down/up/down idle issue--is this occurring only at idle and when you step on the brakes? Or, is occuring at idle even if not stepping on the brakes? If the coolant is low enough and the coolant temp sensor on the intake has an air pocket around it, it will cause the idle to do this. If coolant is full, and the idle issue only happens when stepping on the brakes, it is becuase hot idle speed is too high (either because the idle adjustment screw is set too high or something else is affecting idle speed).

Either way, check your coolant immediately. You don't want to risk overheating.