Came in on a hook with a no start complaint....
Had Coil Primary Circuit codes for all 8 coils, Checked for voltage at a couple coils.....None found.
Found the 15amp Ignition Coils Fuse blown along with evidence that the circuit had been under some continuous stress as the plastic portion of the fuse was a little melted.
Installing a new fuse got the truck running, Idled just fine. Test drive revealed it's barely driveable....REALLY bad misfires. I didn't want to get stranded so I turned around.
I used a Low Amp Clamp at the fuse connected to my Vantage Pro, Average Amp draw was right around 10amps, With the "Multi Strike" coil firing at idle that Fords use makes it a little hard/impossible to accurately average the continuous current draw. But what I saw looked pretty extreme from a current standpoint BUT the waveforms/patterns looked uniform!!
I started leaning toward a bad connection/low voltage condition in the Coils power circuit, I whipped out my trusty Halogen headlamp bulb & load tested the circuit at all eight coil connectors.......Nice & bright!!
OK.....My thought process.
*I'm not dealing with shorted coil/s as the waveforms looked uniform.
*Eight separate PCM driver/transistor issues......Not hardly a chance in Hades!
*Eight degraded coils or all eight are leaking secondary voltage? That seemed far fetched.
*Spark Plug erosion....Vehicle has 96,000 miles & I doubted platinum plugs could erode that much given the normal service table calls for plugs at 90,000.
I decided the easiest thing was to pull some plugs, Sure enough they were in VERY bad shape with a gap you could drive a bus through!
Eight Motorcraft Coils & Plugs fixed the misfires.
![[Linked Image]](https://i.imgur.com/nSTnc1Y.jpg "[Linked Image]")
Had Coil Primary Circuit codes for all 8 coils, Checked for voltage at a couple coils.....None found.
Found the 15amp Ignition Coils Fuse blown along with evidence that the circuit had been under some continuous stress as the plastic portion of the fuse was a little melted.
Installing a new fuse got the truck running, Idled just fine. Test drive revealed it's barely driveable....REALLY bad misfires. I didn't want to get stranded so I turned around.
I used a Low Amp Clamp at the fuse connected to my Vantage Pro, Average Amp draw was right around 10amps, With the "Multi Strike" coil firing at idle that Fords use makes it a little hard/impossible to accurately average the continuous current draw. But what I saw looked pretty extreme from a current standpoint BUT the waveforms/patterns looked uniform!!
I started leaning toward a bad connection/low voltage condition in the Coils power circuit, I whipped out my trusty Halogen headlamp bulb & load tested the circuit at all eight coil connectors.......Nice & bright!!
OK.....My thought process.
*I'm not dealing with shorted coil/s as the waveforms looked uniform.
*Eight separate PCM driver/transistor issues......Not hardly a chance in Hades!
*Eight degraded coils or all eight are leaking secondary voltage? That seemed far fetched.
*Spark Plug erosion....Vehicle has 96,000 miles & I doubted platinum plugs could erode that much given the normal service table calls for plugs at 90,000.
I decided the easiest thing was to pull some plugs, Sure enough they were in VERY bad shape with a gap you could drive a bus through!
Eight Motorcraft Coils & Plugs fixed the misfires.
