2001, 5.4 - just started missing during a 3hr run on a dry day (unusual for the UK!!). No CEL showing. No codes. Miss is present at idle until 2000rpm. Plugs & coils less than 10,000 miles ago. Recently the PCV was vibrating (buzzing - could be heard in cab on idle). Going to check for vacuum leaks tomorrow but any other suggestions welcome. Sadly being in the UK means that just popping down to the local parts store for an armfull of goodies isn't on the cards!

 

What brand plugs and coils did you use?

 

Motorcraft plugs, not sure on the coils - I remember they were $100 or so for the set off ebay. Not much help I know.

 

Those are probably the generic coils from Global or Uneek - which people have been having mixed results with. We have been finding that the only coils that can be really trusted are Motorcraft or Visteon. The Visteons are about $180 a set on Ebay from Alanisdeals.

 

I've only heard Fram PCV's buzz like that, - at times VERY loud. That's because Fram doesn't make a proper valve for the modular or essex engines. Way to restricting, constipates circulation. Causes oil usage as well, which is not good for the plugs.

Run just Motorcraft valves. That little $5 part can be crucial to the way she runs.

Yea, I agree, could be a coil as well.

 

Thanks guys. Global rings a bell, pretty sure that what the coils are. Reckon I'll put an order in for a coil set and the PCV.
Just been playing with the vacuum hoses etc, spraying with wd40 whilst running - no increase in revs or change of engine note. As an aside my father wants to change the fuel filter (its his truck now, was mine) as that hasn't been renewed for a while,however, I can't see this being the fault as it runs sweet over 2000rpm, unless you tell me otherwise?? Having issues releasing those damn clips on the filter - no-one over here stocks them.