I recently changed out my Spark Plugs and Wires. The Wires had a 1999 Date on them (dont' think they were ever replaced). The Plugs looked like they were changed out to Bosch(bullshiat)Single Platnum Tips. When I replaced everything, I noticed the idle in the truck went away. The 4Runner runs smooth as silk and has a little better giddy up(front the seat).
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+1. My wires were original and someone had installed Bosch single ground plugs. The truck was running fine but defintiely has smoothed out and feels a little stronger now. Well worth the time to change things out.