u/Ashamed-Alternative2

Hey, I just noticed two months ago or so, every time my heat comes on, I swear I can smell car exhaust carbon monoxide, right?But i've had p s e and g out here two times and they tested, they said there's nothing but I have also been suffering from headaches.Is there any other gas that I could test for, to see what the heck it is?But I swear it smells like car exhaust to me.