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john, The Car Guy
Category: Toyota
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Experience:  ase tech over 15 years in the field
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1999 Toyota 4Runner: 6 cylinder SR5..misfiring..coil pack

Resolved Question:

I've got a 1999 Toyota 4Runner, 6 cylinder SR5 with a misfiring cylinder. My mechanic recommends replacing the coil pack, and suggested replacing all three CPs if I'm going to do one.

I'm not finding "coil pack" but am finding "ignition coil" on some of the parts websites.

Is that the same thing? And is the price of $70-$90 for one coil pack covering two cylinders or for 3 packs that will do all six?


Seattle, WA
Submitted: 6 years ago.
Category: Toyota
Expert:  john replied 6 years ago.

the coil does one cyliner on the 3.4 v 6

the coil is also refferd to as coil on plug or cop or just a coil

i would just replace the bad one

the coil can be tested with a ohm meter to see it its good


  1. Using an ohmmeter, measure the resistance between the positive (+) and negative (-) terminals.
  2. graphic


    1. Using an ohmmeter, measure the resistance between the positive (+) and high-tension terminalsgraphic
    2. graphic.
Customer: replied 6 years ago.
When I took the 4Runner to my local mechanic he showed me where the wire insulation was getting worn on the line from the coil pack, which he said distributed charge to two cylinders. Instead of replacing the coil pack he manually reduced the gap on the misfiring plug, saying that the worn insulation was reducing voltage from the coil pack to the plug. His solution worked for a couple of months, but the cylinder is misfiring again.

The line with the worn insulation looks like the "ignition coil connector" on your first diagram. Don't the six ignition coils go back to three coil packs?
Expert:  john replied 6 years ago.
it goes back to a ignitor
Customer: replied 6 years ago.
I'm sorry, John, but I'm just not getting it. What is a coil pack? It's not on your diagram, but there are three on our 6 cylinder engine.
Expert:  john replied 6 years ago.
does your system look like this?graphic
Customer: replied 6 years ago.
that looks right
Expert:  john replied 6 years ago.

ok furtherf research does show the coil does fire 2 cylinders, it fures a plug on the other bank or opposite cylinder head thru a ignition cable. So get three coils and a ignition cable set

so it would be 3 coils and 3 plug wires to replace the system

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