Hey guys i am new to this forum and new to electronic controlled engines

i have a 2001 f-350 with a 5.4l v8 that is missing at a idle and hesitating under acceleration my truck has about 70,000 miles on K&n cold air intake and a superchips programmer and gibson cat-back exhaust. i have have 3 people look at it and no one can tell me anything but it must be a coil pack. there is no lights or codes reported. i have changed the fuel filter and there is no change. please help me because this is very upsetting. this truck used to run awesome and get 17 mpg. now i'm gettin like 10 mpg.

i am very inclined to fix the truck my self if some could tell me how to test which coil pack is bad or what else to look at.

thanks again for any help you can offer
here is my vin if it helps 1FTSX31LX1ED38105

 

If indeed it is a coil pack, and you have a light load miss, a good quality code reader will pick up a "pending code," telling you the bad cylinder. Many of the cheap code readers, such as many of those a parts store will let you use, will not pick up those codes.

My Actron CP9135 will pick up these pending codes. $95 at Amazon. ($179 is the list price)

Some people here have said that yanking different spark plug cables to try to find the bad cylinder may disrupt the electronic control. But, I don't know. Sorry.

 

Apparently COP problems are so intermittent that they frequently don't throw codes. What has become the most reliable backyard approach is to buy one new COP and rotate it through the cylinders.

 

The miss of course is causing the hesitation. one by one unplug each coil pak or injector and see how it runs with that cylinder dead. plug back in and continue the rest. when you find one that doesn't make a differance swap the coil with one that does make a differance. then recheck by unplugging each again and see if the miss(dead cyl) followed the coil pak. I fit did follow it replace the coil, if not look at the injector. It could be clogged. Also how old are the plugs? Hope this helps

 

the plugs are original i have hooked it up to my programmer and a mechanic friend has hooked it up to his snap on (i dont know the model) neither registered a code or precode that i know of

 

I wouls start with some new plugs while your at it. Don't worry about it not throwing a code. I bet the plugs are trashed

 

Thanks for all of the postings on the coil problem. My 2002 F250 4X4 5.4L with 65,000 all of a sudden came down with symptoms you guys described. Not wanting to fork over the $ for an ODB II reader. I did the coil swapping as everyone described, unfortunately it was cylinder 4 (left rear) which is the hardest one to reach and the last one I chose to swap.

My recommendation is to change out the spark plugs and the boots since you are removing the coils. Also don't forget to use anti-seize compound on the spark plug threads. Because of the limited space you need a set of 3/8 and 1/4 in sockets and several extension both long and short and a 3/8 flex adapter. The 1/4 in sockets are needed to get at the coil screws, the 3/8 sockets won't clear the fuel rail on several of the cylinders. You will also have to unclip the fuel injector wires to get access to some of the coil screws. The PCV hose will have to be removed and pushed to the side to get at cylinders 3 & 4. I could not get a torque wrench on cylinder 3 & 4 so be careful. Also use your fingers to install the spark plugs. If they don't screw down with finger pressure you maybe cross threading them, back them out and try again. Once you are certian they are not cross threaded you can torque them down. This is an all day job since you test drive the truck after you swap each coil.

Note: I used the bosch platinum 2 plugs which you don't need to set the gap.

Thank you for you posts!