weird symptoms

[wcm7823]

my 03 5.4l expy started acting real sluggish, not wanting to rev, acting like it had bad gas. cel came on, got it read #6 cylinder misfire. and its not a gradual thing. parked it wednesday night running fine started acting like crap thursday taking the kids to school.

i just replaced a coil on number #1 cylinder last month and the only symptom i had for that was a slight bump in the vehicle going up hill.

could it only be a bad coil?

 

[bedrck46]

Could be, and also could be a bad boot or connector or even injector or its connector When was all plugs changed?

 

[FordandPolaris]

If you have a dead miss (usually required for the CEL to come on) you would get some serious hesitation since the motor is only running on 7 cylinders with each cycle. Does the motor feel like its shaking when idling? My guess is that it is a plug/coil issue. If the answer to bedrck46's plug question is "they have never been changed" then you probably will see them go one-by-one like they are now until they are all replaced. They tend to wear out around the same mileage, and 140k on original plugs is a lot.

 

[metaldrgn]

why did you change the #1 cop? Whens the last time the spark plugs were changed? What faults are you getting if any?

You can replace or swap the #6 spark plug and swap the cop with #5 or whatever is easiest to see if the problem moves or if it was just the plug.

 

[wcm7823]

i changed the #1 a couple of months ago because we would get a "bump" in a high gear going up hill. thought it was a transmission issue but finally cel came on and indicated misfire on #1. replaced it and everything was perfect. the engine ran fine until a load was put on it. thats why im not as sure about this coil as i was about the first one..

this time its hesitating real bad, rough idle, i can see the engine kinda shaking at idle. almost like bad gas.

i am away for work but plan on working on it next weekend. ill keep ya informed

 

[metaldrgn]

It may be time to change the plugs. How many miles on them?

 

[whipper]

my 03 5.4 doing the same thing. Going to replace the coils and plugs together and see what happens next week.