Ridiculous misfire please help!!!
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Ridiculous misfire please help!!!
Ive owned this truck for about a year now and ive been dealing with this misfire ever since. truck is stock besides mufflers and lowering kit. this misfire only happens at idle and it only happens after ive driven it for a while or when its really hot outside. ive replaced the spark plugs and the coils (twice). the first time i ordered MSD and i heard they were crap so i figured the heat had destroyed them so i replaced them with motorcraft coils. it mainly sticks to coils 5 and 6. it can start with 5 and then 6 will start or it can just be 5 or vice versa. the codes i get every time are "ignition coil E (or whatever cylinder is misfiring) primary/secondary circuit malfunction". today it was ignition coil "E" that was misfiring so i left it running and unplugged the coil and nothing changed. i hooked up a multimeter to the coil connector and voltage was bouncing all around. not sure what the voltage is supposed to be but it didnt seem right. it seems like a heat issue to me but i have no idea how i would solve it. looking for some advice on how to proceed. thanks.
Fleet Owner
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i hooked up a multimeter to the coil connector and voltage was bouncing all around. not sure what the voltage is supposed to be but it didnt seem right. it seems like a heat issue to me but i have no idea how i would solve it. looking for some advice on how to proceed. thanks.
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Damn sorry about that! I've never posted in a forum before and I did put my truck information in my profile when I created it I thought it would show all that when I made a post. It's a 2003 lightning. 5.4 supercharged. Engine is stock.
Fleet Owner
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Look for a 42-pin connector just below the front of the driver's side cylinder head. I believe the coil wires run forward, then drop down and run through that connector. Being at the front of the engine and near the exhaust manifold there is somewhat of a probability it is dirty or damaged.
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Look for a 42-pin connector just below the front of the driver's side cylinder head. I believe the coil wires run forward, then drop down and run through that connector. Being at the front of the engine and near the exhaust manifold there is somewhat of a probability it is dirty or damaged.
So I don't see the 42 pin connector. And it looks like the coil wires go back towards the firewall
Lead Driver
Joined: Sep 2006
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The computer signal leads are going open for some reason or the PCM has a fault.
The computer coil drivers provide a ground to the coils in fire order.
When the ground is opened the coil fires it's high voltage to the plug.
Your codes tell you these circuits are in fault.
It's not plugs or boots.
The computer coil drivers provide a ground to the coils in fire order.
When the ground is opened the coil fires it's high voltage to the plug.
Your codes tell you these circuits are in fault.
It's not plugs or boots.
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