I have a 2005 police interceptor wit a lil over 100k on it an im gettin a misfire code for cylinder number 7 i put new spark plugs in changed the coils around an put fuel injector cleaner in it the check engin light went off for a min but came rite bak on can anyone help me wit this problem

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.

Have you replaced your spark plug wire?

Check the cylinder compression on the whole engine for starters.

Check Engine Light On, P030x Specific-Cylinder Misfire Code A cylinder specific misfire indicates that either compression, appropriate fuel mixture, or spark is missing. Start with a visual inspection, looking for a vacuum leak near the cylinder and any sign of wear on the spark plug wire. Check the compression on the target cylinder to ensure that the engine is mechanically sound. Use a stethoscope to listen to the suspect cylinder's fuel injector. Listen for distinctive clicks and compare to another cylinder.

Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.
A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Symptoms Symptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Causes A code P0300 may mean that one or more of the following has happened:

• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Stuck/blocked EGR valve / passages
• Faulty camshaft position sensor (more than likely your culprit)
  
• Defective computer

Possible Solutions If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

Check your spark plug and your spark plug wire for that cylinder. The plug may be fouled or the wire may be burnt.

This is caused by a defective cylinder head cam cover gasket, this allows oil to leak into and fill the well the spark plug is in and short out the cylinder, replace the cam cover gasket.

Spark plugs are not your problem

There are no letters on an LS cylinder
codes.

You won't likely have two bad COP Coils
and maybe not the #3 or#7

If not, you have to walk a new coil to find the
bad cylinder

I wouldn't worry about the 02 code it will clear when you replace the coils. to be positive that the coils are bad, swap them with another cylinder and see if that cylinder misfires. 90% of the time it's the coil. Let me know
Randy

Make sure to Replace the Rings also and they will be Fine unless the Heads are Warped.