Car hesitates when cold

I have a 2005 Ford Taurus that hesitates when cold. It feels like the car is starving for fuel, but then recovers and runs fine. I?m going to replace the fuel filter. The car has 66K miles, so it?s probably due.

Here?s my question. With fuel injection, if I let the car sit over night, do I still need to relieve the pressure in the fuel line? Should a certain amount of pressure remain in the line even if the vehicle sits for an extended period of time?

Just throw an old rag over the filter to fuel line connection, as you are pulling them apart. Some pressure will remain. The rag will keep gas from spraying in your eyes.

You can also find the schrader valve for the fuel rail (looks like the valve stem on your tires), wrap a rag around it, and use a screwdriver or something to push in the valve core. That will release the pressure - it might be easier depending on the location of the fuel filter.

Are the plugs and wires also original? Air filter?

Did you check the air temp or coolant temp sensor? Bad temp readings will mess up the fuel mix. Also make sure when warm that the spark is steady on all cylinders. This car is totally controlled by the computer. The computer makes a choice based on the sensors. A bad temp sensor will cause this issue but so will a bad wire or connection. After closed loop on the o2 sensor the temp based fuel rich/lean is no longer active so the engine runs better.