Maybe there is something (mold or whatever) in the air ducts? If you had no issues before it seems unlikely that a filter is the answer. I think there are some disinfectant/deodorizer products that you can spray down in there, maybe try something like that?

 

CLEAN AIR KIT
https://www.autogeek.net/clean-air-fogger.html

 

Air purifier.

 

Thank you...

 

OMG! Thank you sooooooo much. I had already tried a rather costly spray someone suggested and I thought nothing else was out here to help. I kept telling my family and friends I needed some that STAYED in the truck that cleans the air and we couldn't find ANYTHING OUT HERE. I've been getting really sick, coughing and wheezing. I thought my driving for Uber was going to be over! I KNOW this is what I need! I love you and don't even know you!

 

Thank you TAINTER!I I'll use this too, then keep the other product inside the truck permanently. I'm really happy I found this group!

 

Thank you!

 

More info for you:
Cabin filter only filters the outside air entering the cabin.
Sprays are used as a temp masking the odor.
Use an air purifier, and recirculation button:

 

Wearing your significant others panties over your head helps clear the air...

Seriously no...

 

get help for yourself