Thanks for the forum - this is my first post. I've searched for the answer and checked the forum rules/etiquette...hope my initial post is "in bounds." Happy to be corrected if it's not.


99 4Runner with V6. 171K on original engine. Purchased used at just over 100K. Replaced timing belt and water pump at that time...that's the only thing mechanically I've had to do since owning it.

Noticed a slight miss the other day that has gotten gradually worse and more frequent. Finally posted a code: cylinder 3 misfire

I replaced the plugs last night (gapped at .040). Still missing. (The three plugs with the coils were NGK and the three on the other side were Denso...assuming someone had replaced one side at some point).

This morning I replaced the 3 feed wires that go from the coil wires to the other three plugs with NGK wires. Still missing.

My next step is to replace the boots with the coils on top. Am I heading in the right direction?

Thanks again for the help!
Michael