# cylinder 3 misfire

Check to see that plug wire is fully seated on plug and coil pack..Then, pull plug to see if fouled due to not firing when pack was bad.

P0300 multiple misfire
P0302 misfire cylinder 2
P0306 misfire cylinder 6

Is the computer code coming up as a misfire or are you actually feeling the misfire when you drive? Make sure all the grounds for the coil packs and engine are solid and clean. Many times there is rust corrosion under the pack or the retaining screws etc, Low compression can feel like a misfire as well. If all items are OK do a compression check to verify its not an issue.

that would be bad coil packs ,try switching coil pack cylinder 3 with 4or 5 and see if miss fire code changes if it does it's the coil pack .or its possible where they plug in at the bottom(there should be a small oval rubber gasket on coil pack to keep out corrosion or possible not making a good connection (loose) ,oil getting in there ,you can use a timing light to narrow it down faster, pull your plugs for those cylinder and inspect for damage or fouling.and lastly check your wires if any brakes or crakes and that they fit on plugs tightly.

If # 3 cylinder has spark at the plug it must fire if the following conditions apply. Injector is supplying fuel to the cylinder. and cylinder compression tests OK . So check above ,one or both must be at fault.

You said you changed the coil pack and the wires but didn't mention the plugs. Try moving one of the plugs to a different cylinder and see if the miss follows it. It could also be the ignition module. (the thing the coil packs mount to.)

If your car is miss firing and your husband changed the coil packs,the wires leading from coil packs to sparkplugs must have got crossed.This will change car timing which will result in the car miss firing.He needs to go over wiring and correct problem for car to run right.You can go online to autozone.com and type in Info about car to get the correct wiring layout.Your problem isnt the new plugs n wires.Its the wiring layout.

Check the coil packs on the plug if equipped with that type, or the coil packs at the end of the spark plug wires, if so equipped.

Also, check that the fuel injectors are firing on all 8 cylinders.

Definitely, check out what other codes are stored in the computer besides a missing condition.

I have a 1999 Expedition that had a miss on a cylinder, and it turned out to be a bad coil pack. You have 2 cylinders missing, so I would check each cylinder for good spark, or replace the coil packs as necessary to see if that resolves the problem.

Good luck on this repair.

had the same thing with my crown vic on the #8 cylinder. changed plugs and wires. still missing. wound up replacing the coil pack. you can check resistence of the coil between companion spark plug towers. ford marks each tower with 2 cylinder #'s. resisistence should be around 10-12 ohms

Start Small work to Big = Saved Money!
The Code(s) should be telling the specific cylinder(s) that are misfiring. Do you know waht the code is?
Target those cylinders 1st before testing the unaffected cylinders.
The following should isolate the problem(s).
1. Spark plugs - take out-reconnect back to wires and test spark plugs for getting sparks. If none: Don't replace them yet. GO TO 2. If the spark plugs are worn, dirty them replace them.
2. Remove spark plugs form end of ignition wires and test for spark from the wire. If none: Don't replace them yet. GO TO 3.
3. Remove the wires from the coil connection and test the coil for spark for each cylinder. If none: Don't replace it yet.
4. Test each spark plug and wires this way.
5. Coil Packs normally provide fire for 2-cylinders at the same time. The two are paired across from one another.
6. Test the coil for fire, amount of fire and if there is both cyclinders firing.
Misfire and the O2 Sensor got replaced??
Good Luck and get back with me if you need additional help or if this solved the problem.