My 2014 Ford Explorer with 5000 miles allows Carbon Monoxide CO to enter the cabin when the rpm's go over 4000. This happens on somewhat aggressive acceleration and even when the cruise control was set at 60 mph and I had to climb a long hill with 3 adults in the vehicle. The vehicle has the additional rear AC / Heat Option.
This is easily repeatable by setting the main AC to MAX AC, recirculate, set digital thermostat to 70 degrees and set rear auxiliary AC to cold and medium fan speed. Start out with an aggressive acceleration until you reach about 60 and then let off the gas & coast a little. You don't even have to floor the accelerator. Then let vehicle slow down to 40 mph or so and hit the accelerator so it kicks down a gear or two to allow the rpm's to go up to at 4,000 rpm's & you will find yourself smelling a pretty strong odor of exhaust.
I am just driving the vehicle the way someone might if they have to merge into traffic on the interstate and/or if they have to pass someone on the highway. I am not abusing the vehicle as I do these tests. If you're smelling exhaust, logic & physics tell us there is also CO in the air. I notice that the smell of exhaust goes down over time (or I get used to it), but the CO stays present on the meter until I roll down the windows.
The professional grade CO Sensor I borrowed from a friend that owns a HVAC company confirms the presence of Carbon Monoxide. Ford sent their own Technician and stated they could not replicate. This video was taken after the Ford Technician checked out the vehicle and they denied my claim. Yes, I understand my daughter was with me, but I wanted to get this video made and have someone hold the sensor in the mid cabin to get a good middle reading of air. I now have to drive my vehicle with the windows down and do not let the rpm's get over 3,000 nor do I use the cruise control.
The first time the vehicle went into Ford service, they applied the TSB 14-0130.
The second time they had a Ford Technician brought in to test the vehicle. He said they did not find anything. In fact, they loaned me a 2015 Ford Explorer in the identical setup with 80 miles, and IT DID THE SAME THING. They then gave me an Edge to drive for the 3 weeks it took for the Ford Technician to come into town.
Almost 10 minute video, but I wanted it to be one contiguous video clip with no interruptions. If you want to skip the countdown & clearing of the sensor, skip in one minute.
You may notice me hit the Green Enter key some times. This is to keep the unit from shutting down, which would require me to do another 60 seconds of startup time that is supposed to be using outside, ambient air.
Youtube:
https://www.youtube.com/watch?v=z1KIBl6iX-E