MISSFIRE I HAVE A 2000 ACCENT I KEPT GETTING CODE 300 IVE CHANGED PLUGS, WIRES, COIL PACKS. CHAT DOSE THE EGR VALVE DO AND COULD THAT BE IT

well that code means ur have a missfire in cylinder one change the wires for the spark plugs that really the only thing i can think off beacuse you have already done the spark plugs and the oxygen sensors and the coil packs

Faulty EGR valves do not cause "false" misfire codes. An EGR valve that is not closing properly can cause misfires (and misfire codes) but they are REAL misfires when this happens.

To understand this, you need to understand what a misfire is and what kinds of things can cause them. It is a very LONG list and I do not have the time or space to get into all that here.

You will also need to understand this if you are going to properly diagnose your misfire codes without wasting a whole bunch of money on parts that you do not need. MANY things can cause misfires other than spark plugs and ignition coils.

I do not know what EGR code you are getting, but I will tell you that in the 37 years that I have been diagnosing and repairing cars, there has only been once that I can remember that I have ever replaced an EGR valve on a Ford engine because the valve itself was faulty. Most EGR codes on Fords are caused by either clogged-up EGR ports or a bad DPFE sensor. Every so often you will find a bad EGR control solenoid or a broken vacuum line, but it is extremely rare that the EGR valve itself the cause. With the exception of leaking vacuum lines and on certain engines, clogged EGR ports (Like the 6 individual EGR ports in the 4.2L engine), none of these causes for EGR codes will cause any misfires.

Also, most of the time when people pull the trigger on the ignition coils on the 5.4L and 4.6L engines, all the thing really needs is new spark plug boots. They get contaminated with oil and water and can cause carbon-tracking on the spark plugs and/or arcing into the spark plug wells instead of sending the spark through the spark plug. It is pretty much the same thing as having bad spark plug wires on a conventional ignition system. You don't throw the coil and distributor away on a conventional system because it needs new wires. Neither should you replace a coil on a COP ignition system that just needs a boot. Some auto makers do not make the boots available seperate from the coil. Ford at least had the insight to understand that people cannot afford the cost of replacing all of their coils just because the boots are defective.

Maybe the coil pack module that the coil packs sit on is bad if it's like a GM.

Changing the coil packs alone won't always solve the problem.

spark control modular,,

the ignition module, it has to be tested and if defective replaced

Have you changed your coil packs?

These cars do have problems with coil packs, have you replaced these yet, if not then i would advise this be your next step. If you can get the ignition plate that goes under the coil packs also.

check your coil packs, my 2000 did the same thing but only on one. take coil packs off and relocate them to new plugs, clear codes and recheck to see if missfire "follows" moving coil pack

misfire only comes from the coil packs.. replace them

try having the crank sensor tested and the coil packs hope this helps