I'm thinking the PCV system isn't working properly. Give us the the year, make and model to help us answer that one.
Sounds like a leak on the suction side of your equipment.
pluged filter, dirty coils,
None. Those engines draw so much air a filter would be sucked into the engine.
Filter installed in some vehicle to filter the air coming into the passenger compartment.
Yes if it is submerged or you stuck a water hose in the breather inlet. Or maybe its possible if the vehicle was driven through water too fast, maybe.
You can put a performance air filter in your diesel engine. Most engines have several different air filters that can be used.
what size engine is it i have the same car,ive did it , but the air filter is in different places for different size engines, i have 1.6
the air filter is under the hood unless your asking about the cabin air filter for the inside air that's coming in for the ac system its behind the glove box
Is there a flame in the furnace. Precisely where is this air coming from and how strong is it?
The vehicle maintenance schedules will dictate how long a given air filter is supposed to be changed. For instance most of the Chevrolet engines require the change pf the engine air filter after every 45000 miles.
No, but it help filter water.
lots of GM v-6 engines.