Dkoehl26

I recently purchased a 2006 5.4ltr. I am having all kinds of misfire problems with it and not throwing a cel. I have replaced all cop and spark plugs. Checked throttle body to make sure it was clean. After replacing all the coils and plugs the truck ran good for 3 days now it's back to misfiring again. Any help would be greatly appreciated.

SCORGE

Mileage on vehicle? What brand parts did you use?

Dkoehl26

121k put orielys coils in it and motorcraft plugs

SCORGE

Can you better define your misfire problems? Bucking, shaking, idling erratically, etc? How often does it do it? Does it only do it under certain conditions? (Providing as much detail as possible will help in determining probable cause)

Dkoehl26

Shaking at idle and around 45-50mph if you slightly accelerate it feels like a misfire

Dkoehl26

Almost like a shimmy

SCORGE

Assuming plug change went without a hitch? Properly torqued, etc?
What brand COP did you get from O'reilly?
Also, were these symptoms here prior to plug/COP change? Or is it new.

Dkoehl26

They are brake best. Spark plug change went ok I broke 2 off in the head and bought the extractor got them out just fine. I had a shop do the number 8 cylinder because I didn't want to mess around with it in my driveway

SCORGE

Never heard of "Brake Best". BWD maybe?

SCORGE

Was it doing this prior to change?