code P0304 misfire

How do i fix a diagnosis code P0304 a misfire in 4 in a 1996 Taurus with 3.0L compression good 120 changed plugs wires egr backpressure sensor vacuum solenoid vehicle speed sensor coil pack injector switched injector wires cleared codes, got same code only P0304 comes up what else?

thank you,
Robert

You say compression on #4 is at 120? That sounds like a very tired engine to me. What did it measure on the other cylinders? Did you see if adding oil would make the compression jump up, and remember to keep the throttle wide open while doing the test? Your car is at the right age to start developing some engine wear problems.

120 ALL ADJACENT CYLINDERS ON BANK ONE, I HAVE NOT TRIED THE OIL TRICK YET AS ALL WERE RITE WITH IN EQUAL PRESSURE.

Cylinder #4 is on bank2 are you working on the correct cylinder. #4 is the first plug on the radiator side of the engine.

hi,
yes i am working on the first cylinder front of car passenger side closest to the alt, another question ive taken the injector plug wires and switched them number four 4 with number five 5 and i still get a reading of P0304, which means number four 4 cylinder, question i have is are the injector wires married to or assigned to a specific cylinder? or could i put ANY injector wire to ANY injector? if so in theory wouldnt number fours 4 wire become number five or would number four 4 even tho hooked to 5 injector think it was number 4 still? have i confused you yet??????? what im trying to say is if i move four to five does it (PCM) still think it is connected to four when in reality it is connected to five?? or does it sense it is connected to five and not four where it use to be connected.. and still give me the code P0304 or since i switched injector wires being hoofed up to five IF it was in the wiring it would read P0305?? and if in the cylinder it would still read P0304. hope this made sense???? if you or any body would like to call me let me know your email and i will send it to you so i can try to explain what i have written above??

thanks so much for your time

Robert

you can move any injector to any cylinder but the plug needs to remain in the same spot.

so that would be a yes?? to the last question i had above??

if i moved injector wires from 4 to 5 and 5 to 4 and still got the code P0304 what am i missing here??

if it was in wiring? it would have read 5 rite?? and if in cylinder it would have stayed 4 rite??

because if wiring!! it would have transferred the code to number five rite?

and if in cylinder it would stay 4?

unless the wiring for injectors are married to or must be connected to the assigned cylinder for the assigned injector??

What asecmt is saying is that you can move an INJECTOR to any cylinder, however, the INJECTOR WIRING must remain with the designated cylinder.

It's the same as changing/switching spark plugs to any cylinder but the spark plug wire has to remain with the cylinder that it's mean't for.

Switch the injector wiring back to the original configuration, ascertain that injector #4 is receiving the signal through the injector wire for #4.

If it is, switch INJECTORS between cyls 4 & 5 and see if the code changes to a PO305.

If the code changes, then you know you have a faulty injector.

Good luck and keep us posted.

sorry should have mentioned that too,

yes i did change the injector in number four, and switched wires before and after injector changed

WOW

Injector connectors can not be swapped from cyinder to cylinder on the engine because at idle only one injector is fire at a time. Thus if you put 4 on 5 and 5 on 4 , cyl 4 will be given fuel when cyl 5 is supposed to get fuel. Have you checked for battery power to the injector? Have you checked for injector pulse signal the cyl 4?

the injector will work then shut off, then come back on the shut back off, i can hear it clicking then for no reason with engine warm or clod it will shut off then for no reason hot or cold it will start working i have changed injectors and put in a new one,

Robert

I am thinking a wire problem in the injector harness or a bad injector driver in the ecm.

changed injector, ohm"ed out injector wiring, working fine no issues

so the first "new injector" was faulty?