My truck has a jerking (missing) problem

[redman]

I have an '02 F150 super crew 4x4 with a 5.4 motor. I replaced all plugs and one coil pack about 10 months ago. I don't have any aftermarket stuff on it other than a magnaflow muffler that i had put on in March 2010. It has now developed a jerking (miss) code says "line of fire" on number three cylinder. I put two new coil packs in, and after about 120 miles it goes to missing again. I changed brands and replaced it again. This time we made it about 400-500 miles and it started missing again. When you replace the coil pack it runs good for a while, but then starts up again. I am thinking the plug is ok because it smooths out for a time. PLEASE HELP!!!! My daughter needs this truck to get back to school (350 miles away!) next weekend! I am at my wits end trying to figure this one out. The truck has about 130,000 miles on it and has been great up to this point.

 

[d-kuzmen]

Are you running a Ford coil pack on it? You may also want to change the plug at the same time there maybe an issue with the plug causing the coil to go bad.

 

[blacksnapon]

Are you running a Ford coil pack on it? You may also want to change the plug at the same time there maybe an issue with the plug causing the coil to go bad.

I agree. A plug can cause coil failures.

 

[redman]

I replaced the coil pack again today as well as the plug on #3 (the code reader keeps telling me it is this cylinder). Fired it up and it ran good for about 6 miles, then started jerking again. Basically, when you are running at a steady speed and go to accelerate slightly is when it is the worst. I ran it with the code reader on it and it is not showing any codes and the check engine light did not come on, but I think it is running worse since I changed the plug and coil this time. I also removed the air filter to blow it out, and left it out and drove it a few miles and the jerking got even worse - I've got a new filter coming tomorrow. Could it be the MAF sensor? HELP!!!!!! Thanks for the previous advice and any help you can give me!

 

[blacksnapon]

I replaced the coil pack again today as well as the plug on #3 (the code reader keeps telling me it is this cylinder). Fired it up and it ran good for about 6 miles, then started jerking again. Basically, when you are running at a steady speed and go to accelerate slightly is when it is the worst. I ran it with the code reader on it and it is not showing any codes and the check engine light did not come on, but I think it is running worse since I changed the plug and coil this time. I also removed the air filter to blow it out, and left it out and drove it a few miles and the jerking got even worse - I've got a new filter coming tomorrow. Could it be the MAF sensor? HELP!!!!!! Thanks for the previous advice and any help you can give me!

You can try swapping injectors from one cylinder to another. If the miss follows the injector................

 

[d-kuzmen]

I replaced the coil pack again today as well as the plug on #3 (the code reader keeps telling me it is this cylinder). Fired it up and it ran good for about 6 miles, then started jerking again. Basically, when you are running at a steady speed and go to accelerate slightly is when it is the worst. I ran it with the code reader on it and it is not showing any codes and the check engine light did not come on, but I think it is running worse since I changed the plug and coil this time. I also removed the air filter to blow it out, and left it out and drove it a few miles and the jerking got even worse - I've got a new filter coming tomorrow. Could it be the MAF sensor? HELP!!!!!! Thanks for the previous advice and any help you can give me!

Driving with the air filter out will cause the truck to run differently because the pcm knows how much air will be pulled through the filter. when you remove it the air flows differently sometimes confusing the pcm thus the poor running.

 

[d-kuzmen]

You can try swapping injectors from one cylinder to another. If the miss follows the injector................

I agree you can swap injectors see if the skip changes. Also you may want to pull a compression check on that cylinder it maybe weak, you could have a bad valve.

 

[redman]

I was gone over the weekend, but got back on the truck today. I cleaned the MAF and the butterfly on the throttle body. I put in a new air filter. I drove it 7 miles no problems and then about 4 miles back, then it started jerking at about 50- 55 mph under slight acceleration. No check engine light or codes are showing up. I also replaced the fuel filter last week and the old one had some rusty looking gas in it. While I had the filter out, I turned the ignition on and gas flowed freely. With thumb over gas line from tank, it seemed to have adequate pressure. After I got back from my test drive today, I pressed the relief valve in the fuel rail and I only got a small squirt of fuel . If there is trash in the gas tank and it is sucking up against the fuel pump screen, could this be my problem?

 

[blacksnapon]

That could do it too!