Re: P0455 error code, 2002 mustang 3.8L
Hey Bill. Do you still have the problem? I don't even know where the sensor is located for this system, but could it be a bad (overly sensitive?) sensor doing it's thing a little to zealously?
What about slightly pressurizing the system to listen for any leaks?
Just a couple of thoughts anyway. I don't know what that code is exactly, but my older 3.8 ('95) throws codes for every other thing in the book! Never had that one, but, like clockwork, the Check Engine light comes on a month or so ahead of the smog check. So it's scramble-time every two years.