I have a 2005 f150 with a 5.4 and am getting a code po506 what is this!

TYPE: OBD PO506
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OBD PO506

OBD & your codes,that's how you find codes

CRC Throttle Body Cleaner-try that

Check to see if the throttle body is gunked up. If it is, clean it up and see if that fixes the low idle.

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Type: Ford OBD PO506

Thermostat failure, random misfires detected, idle control errors. Severe vehicle overheat condition could set po300 and po506. Recommend replace tstat and seal , clear codes and recheck.

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OBD PO506

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OBD PO506 -- type that

The code 442 is a small EVAP leak such as a gas cap or vac line to the canister.
Code 506 is saying the computer can not raise idle speed to where it needs to be. Could be a faulty idle air control valve or dirty throttle body.

From http://www.obd-codes.com/trouble_codes/
The P0300 is a misfire and P0506 indicates low RPM at idle.

A misfire can be caused by poor ignition (spark plug, plug wire, coil, ignition module/engine control module).
OR
Poor air/fuel (air filter, fuel injector, fuel pressure, fuel filter, fuel pump, bad gas, or engine control module).

Check your maintenance requirements and see if any of these items are due for replacement first.

You need the idle control solenoid replaced. It is the dealer that will fix it for you.

Good luck.