Po304 I scan it say po304 and what is these.

all misfires and bad mixture of fuel and air

https://www.google.com/search?q=05+TAURUS+CODE+SHOWING+po171+po174+po300+pO303+pO304

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Code PO304 means that Cylinder number 4 is misfiring.

The code PO304 means that cylinder 4 is misfiring and it could be that the sparkplug is bad and needs to be replaced or sometimes it could be the sparkplug wire

Replace the COP Ignition Coils

Google the codes to learn about them

Type: OBD PO304

Cylinder misfire on # 4

Google----OBD2 Codes 2004 ford PO304
& learn about that

PO304--- Possible Bad Ignition Coil on cylinder #4

PO136-- O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)

Could be sensor or wiring or misfire or other items

You should have changed the front or upstream O2 sensors
on all your vehicles at 100,000 miles

The coil code may or may not be correct
You have to diagnose cylinder misfires

I would suggest a repair shop & they have to use a scan tool
in Mode #06 on a road trip of at least 20 miles, to check for
cylinder misfire counts or use an oscilloscope on a road test

If replacing the coil on #4 resolves the issue, it was just luck,
& luck only goes so far

I had a coil in June that no professional test equip found
I had to walk a new one one cyl at a time

the P0304 means Cylinder 4 Misfire Detected
______________
om580 code reader

PO304 --is a misfire on cylinder # 4
The 171 is an O2 code from the misfire

Care to say what vehicle you have!

Cylinder four misfire. Check your plug wires (or coil packs) and your spark splugs.

po507 idle rpm higher than expected.idle control valve? po304 cyl 4 misfire.catalyst damage. should repair. looked it up in manual.good luck.