Thanks for all of your help with the location of # 5, I was a Chevy man in
my younger days so I was on the wrong side and location for # 5. Now I
changed the pack on the cylinder in question, But now it is still hit and
miss ( no pun intended). Some times it will run fine then all of a sudden it
miss-fires again. My little scanner is telling me "IGNITION COIL C
PRIMARY/SECONDARY CIRCUIT MALFUNCTION" What the hell does that mean and how
do I fix it ?
P.S. what ever happened to the days when you could do all of this without a
computer and scanner ?
Oh ya it might help if I tell you that my odometer reading ( digital ) is
slow in coming on. Some times it's 10 - 15 minutes after you start the truck
before it lights up. It has done this for 2 years now and I never thought it
was a big problem. I wonder if it has any connection with the miss-fire
First... the odo reading.... is it blank and then comes on or does it
display dashes at first and then numbers after a while?
Your ignition concern... might be a little easier if we had the code rather
than your scan tools interpretation of it... I have access to the factory
PC/ED even at home. However, it is indicating an electrical concern.
Possibly spark plug cable or a primary (12V) circuit concern.... I would try
the plug cables as a first thought (you can check the resistance/continuity
of the cables and inspect the insulation for damage/bulges/lightning strikes
(it has new plugs, right? And, at the risk of drawing ire, I use only
Motorcraft plugs in Fords.... ). If these are the factory plug cables, I'd
consider replacing them since they are near or past their expected service
The odo reading only comes on straight from blank it does not show dashes
The truck has no plug wires it only has individual coil packs the truck has
200,000 kilometres on it ( about 130,000 miles ). I have had coil pack
problems before and changed them with no problems after, so this issue has
My bad... it was around the 00/01 MY that the 4.6 was changed from coil
packs to coil on plug.... There is much to be lost in terminology.
Now... have the plugs been changed... if so, what with?
As for the odo display... if the display came on with dashes at first, it
would have indicated a communications problem between the cluster and the
PCM. Since the display is blank at first, it is a sign of impending doom for
the cluster itself.
I agree with Jim. The exact code would be helpful. If I
recall correctly, the PCM can detect a misfire whether it be
electrical or fuel. The codes would be different. I also
think you may have a plug problem. That is the most common
problem other than the COP packs. I strongly recommend
using nothing but Motorcraft plugs in Fords. They are
readily available in most areas at competitive prices. In
the absence of Motorcraft, I have had good luck with
Autolite plugs in Fords. If you have Bosch plugs installed,
I would pull every one of them before you get any more
grief. I have no idea how an otherwise quality manufacturer
can build such crappy junk spark plugs to tarnish their
reputation. Never installed a set in anything that didn't
result in problems.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.