I posted before with this same question, but I have just heard from a guy who used to own a 1999 F250 Superduty with the 7.3 liter diesel, and he had the same problem that I am experiencing now. He also was having an issue with his truck coughing and sometimes stalling when ever there was a light misty fog or a light drizzle. He had told me that his mechanic had found the problem to be with the O2 sensor, and once changed it straightened out and ran fine again. My question now is, how many O2 sensors are there on a 2000 7.3 liter engine, and where are they. Also do you need to hook it up to a snap-on computer to change these sensors. Thank you for any help you can offer me on this problem. Blessings to all, Rob