Can't Get Rid of Engine Roughness - Ideas?

[tdfuller]

Sorry for a late reply, but I had similar problem with my 04 EB Expedition. Actually same codes. I had P0303, P0306, P0174,P0357. I immediately changed #3 and #6 coils. Like you, Expy ran good for 3 Days then back to having P0303 code. Other codes cleared themselves. I metered the old original coils to find that they were still ok. So I changed out the spark plugs, coil boots and springs. Still had P0303. I visually inspected #3 fuel injector. Looked good until I unplugged the electrical connector and smelled fuel. There was fuel leaking at the fuel injector plug. I replaced the fuel injector. The Expy has been running and idling great. No more codes. Hope this gives you an idea to solving your issue.

Thanks Darrr

I have not had a repeat code after replacing the cylinder's coil related to that code error and cylinder, but will keep your tip in mind if I have another repeat of the same code or if rough running engine symptoms return.

 

[mbtech2003]

Thanks for the tip.... Do you replace your own coils?

Yeah. Did plugs and coils same time.