I have had a rough idle on my 04 Blazer LT for just the past few days. I ave replaced all 3 O2 sensors on the vehicle within the last 7 months. There is no fluid leaking under it and levels on the dipsticks are normal ranges. It doesn't run hot. However, as soon as I put it in gear (leaving work, store, etc.) the oil pressure drops from 40 to about 20 and stalled out today in the driveway. That is the first time that it has stalled on me. It almost sounds like an exhaust leak coming from the passenger side of the car. Any suggestions as to what it could be? Also, it is just under the 100K mile mark, if there are any problems associated with that milestone.