A week ago i bought the expedition and we knew there were are few things wrong with it tie rod ends and needed tires , and the motor and trani were rebuilt in 2009 there is only 60,000 miles on both of them. well the check engine light was on and had a very small studder took it in and autozone said 02 sensor bank 2 number 1. And also a misfire on number 3 so we got it home and changed all the spark plugs and 02 sensor and the coil pack for number 3. Light came back on and said same 02 sensor and misfire on number 8. Changed the coil pack for number 8. Still not running right. Rough idle and when you driving it and get to 30 35 miles an hour it starts to studder really bad the whole truck starts to shake. Took it to a garage and it took them 4 hour and 280 dollars later to tell me there is still a misfire on number 8 and it must be an "internal misfire" what the heck could that be???? I dont know what else to do. But i need i running truck now! Please please help me. My husband is sock of working on it and no change at all

 

Try pulling unplugging the injector for the cylinder with the misfire if it changes the way its running injector is working if no change injector is might be bad

 

Hey

My 2004 F250 5.4L started doing the same thing this week. Check engine did not light up until today and was giving me P0302 and P0171. Misfire on cylinder 2 and lean on bank 1. I personally think its just a bad coil on mine.

You can get a bad coil out of the box, might want to pull all 8 and bench test them. I would only recommend a an OEM Motorcraft coil, about $40 from rockauto or $70 from a parts place.


Also might not be a bad idea to do plugs and injector o rings. Gives you a chance to clean everything up in there. Inspect the intake manifold for cracks.

Use dielectric grease on the o rings and coil boots! Also clean the MAF sensor.

You dont need any special tools for this job. Just some time.

 

Found this video, quite a bit of work, but maybe this could be your problem.

 

The most common thing that could cause your problem is plug boot tracking. look for tracking on the spark plug it will look like a black trace from the top of the plug to the base. you must replace the plug and boot at the same time or it will happen again. also on some late model fords you must clear the keep alive memory as the computer can shut off the injector driver for the missing cylinder in order to save the cat from damage. you can also test the coil by leaving the coil out of the plug hole and run the engine it should produce a 2 1/2 inch blue spark about 40,000 volts. weak coils are the second most common cause for miss.

 

I have a simular problem on a 2000 5.4 with 180k miles please read post from F350x2 if you think you can help with it. Thank you

 

Start your own thread in order to have similar problems addressed. Adding something unrelated to an existing post doesn't help it or your issues.

 

just clean the MAF and replace all coil packs (motorcraft) along with spark plugs and wires. same thing happened to my 04 f250 5.4l.