So I replaced the obviously leaking ICP sensor in my new old 99.5 7.3 PSD Superduty and cleaned up the mess it left. Two weeks and a couple hundred miles later, I'm experiencing similar symptoms (most notably oil on the 3 prong plug going into the sensor, and oil in the top of the sensor where the prongs are). I cleaned both plug and sensor top well with CRC Electrical Cleaner, blew it out with compressed air, and let it dry. Both the plug and sensor looked nice and clean at this point. I started the truck and let it idle for about ten minutes, shut it off and pulled the plug off the sensor again - the plug was oily and oil was beginning to gather in the sensor where it plugs in.

The fellow at the Ford parts counter was real good about swapping it out, and I was relieved as the sensor was $240 with tax.

My question is this: Was this most likely a bad sensor (unusual), or is there something else that might be wrong causing the sensor to be over-pressured and fail? The motor is all stock, I haven't driven it particularly hard (a couple near full throttle accelerations in 3rd mostly), and put about 200 miles on the truck since I replaced the first sensor. The truck seems to run very well and be getting reasonable mileage, starts like a champ, no other oil leaks (eg. turbo pedestal and HPOP) are apparent, and no codes are thrown if the sensor is plugged in.

Thanks in advance!