My wife drives a 2003 Ford Focus as her work car. She has a 50 mile commute 5 days a week. Last week she was in town running errands with our daughter and it quit on her. I drove to town and checked the engine code it had thrown. It was PO191 - Fuel Rail Pressure Sensor Circuit Range/Performance. I slowly drove it home noting that it wouldn't rev over 3000 rpm and had a hard time climbing grades. We bought the car with 94,000 miles on it. I changed all of the fluids and filters (yes even the fuel filter) at that time. The car now has 146,000 miles on it. I changed the filter and performance resumed to normal. Today I cut the old filter (Fram G8018) open and this is what I found: