Well a while back I traded in my 2014 ST due to all the issues it had. A few cars later I have come back under the fold with a 2017 ST I got last month from a Kia Dealership. They got the car from Ford supposedly across the street as they knew the dealer (Ford had ZERO STs on the lot as I went there first). The car had 2500 on the clock so thinking well that's cool I am getting practically a new car with low miles. The story was a dad bought it for his kid and then found out the car was too fast for him to have.....mmmkay. It had a little smell to it on the inside but it wasn't major. Well I finally figured out what the smell was after having to run defrost as it gets colder out. Exhaust was getting into the vents when it was circulating air. I figured this all out when testing the different HVAC settings and of course was worse on cold start up. Therefore I knew I had an exhaust leak. Take it down to my local Ford dealer to have them look at it, because the place I got the car from was over 1.5 hours away and why wouldn't someone just take it to Ford that's 4 miles away for assumed warranty work? Anyways, I told them what it was.....4 hours of looking into it they say they found the issue. "Someone put on an aftermarket exhaust previously and didn't put the stock parts back on correctly.....also your O2 sensor threads are bad cause they tried to put it back on and messed up the threads. Our guy is going to try and fix the threads and put it back in. That's going to be about $230.". So I get a call about 45 minutes later, "Yeah, the threads are messed up and you will need a new O2 (which of course they do not have and will get one tomorrow). Your total bill is going to run you about $450.". So $450 for something I had no clue that was done to the car and haven't even made my first payment...let alone the Carbon Monoxide I was enjoying for the entire month (explains the headaches). Called the dealer I bought it from and they are "researching" the issue from the previous owner to see what they can do (Uh the dealer can pay the dang bill I am about to get). This all does not add up though. Is Ford being honest by saying someone did in fact mess with the exhaust and put a different DP/exhaust on it with under 2500 miles? Or was it a manufacturing flaw due to the amount of factory cross-threaded O2 sensors out there? Ugh this is not cool. I would have just fixed it myself, but now Ford has the car and of course wont release it since the O2 no longer fits.