Misfire 5.4 Triton ford

Answer 1

any misfire -- on any vehicle with plugs and spark plug wires-- needs to havev the secondary wiring checked{wires-plugs-cap-rotor if equipped} THEN checked on a machine designed to read secondary ignition voltages------no other solution-especially cannot be done in a drive way situation

2nd answer

What Year Model is the truck? On the 5.4 3 valve engine 2003 or 2004 to 2009 models have a 9/16 spark plug and should be taken to a dealer to have the plugs changed. they are known to have the plugs brake off and special tools are needed to remove then if they break. for this engine it is recommend to change the plugs around 60k to help lesson the chance they will break. the 2 valve engine is a normal 5/8 plug.

All of the 5.4L Triton engines are Coil on plug ignition ( COP )

causes for a miss can be 1. bad coil or plug 2. poor connection (wiring) 3. bad driver in PCM (computer) and 4. mechanical concern with a valve or piston. also bad fuel or injector.

With out the proper computer equipment to find out what cylinders have a miss you can throw a lot of money away trying to guess what is wrong. a good shop or dealer will save you a lot of money.