Hello and Thank you for choosing Just Answer. My name is XXXX XXX I will be helping you with your question today.
Very common on the 4.6L, 5.4L and 6.8L motors is too have 1 or multipe ignition coils go bad cauing the misfire. If you know what cylinders are misfiring, you can try swapping the coils from cylinder to cylinder too see if the misfire changes. If you do not know, you will either have to buy a new coils and just install them or have a local garage use a scan tool and tell you exactly which cylinders are misfiring. Sometimes it is not a bad idea just too change all teh coils at onece as eventually they will all need to be replaced. Coils can range in price from $30-100 depending on where you buy them from.
i know its not the coils as the cylinder misfires change cylinders everytime i read the codes. i have have 6 diffrent cylinders misfiring. when i am at a higher speed and higher gear it seems so much worse but when i flore it things seem ok. i paid $15 bucks to the last guy on here to tell me to change the tps and that did nothing. last time i had this problem i had to clean the mas air flow sensor and the problem went away. i did that this time and nothing changed.
I changed 7 coils and truck still runs the same. It is not getting worse nor better. what about the egr? if there is a leak will that cause this?
I have now changed the mas air flow sensor, tps, all plugs, all cops, fuel filter, a small hand full of vacume lines, I have no egr on this truck, the ticking noise that sounds like an exhost leak is coming from the oil pan and bell housing. I have worked on this problem and have spent lots of cash at this point and the problem still here. ???