Began rough idle out of blue. Pulled in a shop coded #6 coil issue.
Dephi orig part replaced #6 with Denso.
Key turned, no starter just clicking.
Put old part back on, turns over, starts and has same rough idle.
At a loss for this scenario.

When you installed the Denso coil on the #6 plug, are you sure it snapped on all the way? Also, is the battery good?

You might try swapping your original #6 coil with the one from #5 and see if the code moves with it. Then try putting the new Denso coil on #5 and see what happens.

Thx

Any luck?

Wait a minute.

Doesnt this gen truck share coils? I.E. you should have 3 coils and a set of 3 plug wires, right?

If that is the case, #6 should only have a wire going to it.

If my memory serves right, #6 is driver side firewall. And it shares the wire with coil #3, which is pass side middle. So if it just misfiring on #6 and not 3, my first suspicion is a bad plug or wire.

Great catch! You are correct, #6 is driver side firewall and shares the coil on the #3 cylinder (mid passenger side).



OP, check your #6 plug wire as 1agswitchin4lanes said. You can try putting the new coil on #3, and also try swapping the coil on #1 with the coil on #3. All of that can help you diagnose the true source of the issue.

Y'all are spot in about shared coils. Woyold be coil on top of #3 my guess. Are coils interchangeable? Meaning #1,2, or #3 couild be interchanged or are they specific parts?

Yes, they are interchangeable - all 3 coils are the same part #.

Ok, he tried interchanging coils, still very rough idle. Going to change out spark plug wires and connectors next.

Still have not gotten info on the exact code(s) that it was throwing. Son works in Terlingua and is with this truck, so trying to solve long distance issue in an isolated area.

Codes knowledge will help, but could this have anything to do with O2 sensors or injectors? Truck has been well maintained with 141,000 on it.

1agswitchin4lanes said:

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Wait a minute.

Doesnt this gen truck share coils? I.E. you should have 3 coils and a set of 3 plug wires, right?

If that is the case, #6 should only have a wire going to it.

If my memory serves right, #6 is driver side firewall. And it shares the wire with coil #3, which is pass side middle. So if it just misfiring on #6 and not 3, my first suspicion is a bad plug or wire.

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Impressive. I can barely find my keys on a daily basis.

Well problem ended up being a worn out #6 Spark plug wire and boot. It had a shorted out looking burned spot on the boot near where the wire from the coil enters the plug boot. 30,000 miles on the wire, typical wear or something sinister?

allMondjoy said:

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Well problem ended up being a worn out #6 Spark plug wire and boot. It had a shorted out looking burned spot on the boot near where the wire from the coil enters the plug boot. 30,000 miles on the wire, typical wear or something sinister?

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Subpar "jobber grade" wires?