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Discussion Starter #1
okay here is the Laundry list 157k miles:

Code for random misfire cylinder 7
Service traction control
Service stabilitrac
Service traction control
3rd time in 5 months passenger headlight blew out


Started on misfire. Changed plugs and wires, moved coil pack from 7 to 3. Misfire stayed on 7.
Thinking piston rings or valve spring. Spark plug throwing spark.
Misfire stops when some of the wires get moved accidentally so also thinking bad ground.

note when misfire stops all warning lights go off on the dash and engine runs smooth

Appears previous owner had the same issue as many of the wires show signs that a prong type tester was used directly on the wires through insulation to test for continuity.

Reading other forums been finding other owners of this vehicle having the same issue but none offer a solution that worked. One said to replace ground strip however mine appears new and with no corrosion breaks.

Also when testing wires from the computer mechanic said the signal going to cylinder 7 coil pack wasn't right. Could be bad computer but still thinks its a faulty ground some place.

I dont see any recall Info on this issue, anybody else run into this problem? What did you do?
 

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1984 Fleetwood Brougham Coupe, 1999 ETC, 2012 ESV Premium
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okay here is the Laundry list 157k miles:

Code for random misfire cylinder 7
Service traction control
Service stabilitrac
Service traction control
3rd time in 5 months passenger headlight blew out


Started on misfire. Changed plugs and wires, moved coil pack from 7 to 3. Misfire stayed on 7.
Thinking piston rings or valve spring. Spark plug throwing spark.
Misfire stops when some of the wires get moved accidentally so also thinking bad ground.

note when misfire stops all warning lights go off on the dash and engine runs smooth

Appears previous owner had the same issue as many of the wires show signs that a prong type tester was used directly on the wires through insulation to test for continuity.

Reading other forums been finding other owners of this vehicle having the same issue but none offer a solution that worked. One said to replace ground strip however mine appears new and with no corrosion breaks.

Also when testing wires from the computer mechanic said the signal going to cylinder 7 coil pack wasn't right. Could be bad computer but still thinks its a faulty ground some place.

I dont see any recall Info on this issue, anybody else run into this problem? What did you do?
From what I've read it could be the battery cables, there's also a ground under the drivers seat. Look above the front driveshaft to see if the harness has fallen into contact with it, and damaged the wires.
 

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Discussion Starter #3
I've got it at a shop I have taken all my vehicles too. He agreed no way it should require a new engine. He also believes it is a bad ground and has also found other shops in my area have gotten an influx of same make and model with the same problems.

I will go by his shop tomorrow and run the information by him.

Thank you.
 

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1984 Fleetwood Brougham Coupe, 1999 ETC, 2012 ESV Premium
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131 Posts
I've got it at a shop I have taken all my vehicles too. He agreed no way it should require a new engine. He also believes it is a bad ground and has also found other shops in my area have gotten an influx of same make and model with the same problems.

I will go by his shop tomorrow and run the information by him.

Thank you.
Good luck. Keep us posted on what you find.
 

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2014 ELR
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186 Posts
The left or odd bank coil harness runs through connector X111.
It is located just above the valve cover in the driver's side of the engine (see attached photo with red circle)
583538


Pin B has the control wire for cylinder #7

583539
583540
583541


I would check for good, tight terminals in that connector and check the orange wire for corrosion. If the wire insulation has been pierced by previous repair attempts there is a very real possibility the wires are corroded inside the insulation. That will cause the intermittent you describe. IMHO people who check wires by poking something through the insulation should be shot on sight.
 

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Discussion Starter #6
Just a
The left or odd bank coil harness runs through connector X111.
It is located just above the valve cover in the driver's side of the engine (see attached photo with red circle) View attachment 583538

Pin B has the control wire for cylinder #7

View attachment 583539 View attachment 583540 View attachment 583541

I would check for good, tight terminals in that connector and check the orange wire for corrosion. If the wire insulation has been pierced by previous repair attempts there is a very real possibility the wires are corroded inside the insulation. That will cause the intermittent you describe. IMHO people who check wires by poking something through the insulation should be shot on sight.
Just an update, I have been moving into a new house and haven't been by My mechanics to see if he has any updates. I only left this message because I didn't want you guys to think I got it right and bounced.
 

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Just a

Just an update, I have been moving into a new house and haven't been by My mechanics to see if he has any updates. I only left this message because I didn't want you guys to think I got it right and bounced.
Thanks very much... whatever you find, please let us know?
 

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Cadillac
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The left or odd bank coil harness runs through connector X111.
It is located just above the valve cover in the driver's side of the engine (see attached photo with red circle) View attachment 583538

Pin B has the control wire for cylinder #7

View attachment 583539 View attachment 583540 View attachment 583541

I would check for good, tight terminals in that connector and check the orange wire for corrosion. If the wire insulation has been pierced by previous repair attempts there is a very real possibility the wires are corroded inside the insulation. That will cause the intermittent you describe. IMHO people who check wires by poking something through the insulation should be shot on sight.
Are those All-Data circuit diagrams or Mitchells or ?
 
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