So my a14 was just put in my ute it has a big cam extractors 32/36 and exhaust and was running fine for the last few days and yesterday on the way out of work it started missing when taking off then just made a massive bang noise I took spark plugs out and cleaned and got it started but sounded like it didn't have all it's normal power and was missing what could this be ? It has a new coil,alternator ,fuel pump

Could be a cracked piston. Did you have the valve-to-piston clearance checked?

I would give it a compression check.

were you giving it a hard run when it went bang.

Nah just cruising up the street

so is just missing now or does it have internal engine noises(like metal type knocking or what)

Nah it's just missing doesn't want to run doesn't sound like internal

Take the rocker cover off and check for a bent pushrod. Or more. It will also give you a chance to see if the camshaft is turning.

With a problem like that of what you are describing, it it a bit open ended. Too many things that may have gone wrong.