2001 crown vic has a misfire on #5 - 1995 Ford Crown Victoria

The Crown Vic has issues with the spark plug wires, replace them if the spark plug connector boot looks burned or has holes burned into it. Replace just one wire at a time!! Also do you have a check engine light? You should if your engine has a misfiring cylinder.

Engine Misfire diagnosis can be complex and there are many reasons for misfires to occur. I suggest you read the article at this link that deals with engine misfires and the diagnosis of them and possible solutions to repair them.

If the cap rotor and plug wires are original, I would look at them first.
Also check the condition of the plugs.

Check the cylinder compression on the whole engine for starters.

P0304 means that cylinder 4 has a misfire and P0305 is a cylinder 5 misfire. What this means is you may have bad spark plugs, or bad plug wires, or you may need to replace your distributor cap and rotor. I would start with plugs and wires.

For the 1999 Ford Crown Victoria:

For the 4.6L V8:
Firing Order:
1-3-7-2-6-5-4-8
Cylinders:
.......(back).......
'..4..'........'..8..'
'..3..'........'..7..'
'..2..'........'..6..'
'..1..'........'..5..'
.......(front)

The 5 digit entry code is in the trunk, on the left hinge arm that holds the trunk lid.

your egr on that side is dirty try cleaning it aslo check intake boltsaround those clyinders.

I just came up with that exact issue in my 2003 with 98K police crown vic. And the last time I had this issue in a 2001 police Crown vic it was the crank shaft position sensor. A $20 part and about 30 mins to put it in. located near the bottom of the engine. I had to un bolt the A/C compressor and push it out of the way a few inches to get to the sensor. If you have about 100K mile on it and its an idled heavy police car, this sensor should be changed out anyway. It can leave you on the road dead and some dealers have a hard time find out whats wrong as the OBD 2 does not see it as a problem when it goes bad or becomes touchy as I think mine is.

where is the fuel pump relay on a 2001 crown vic p71