Replaced original plugs at 142,xxx miles

[JimD]

Replaced the plugs (and wires) in my '98 recently. Since I expect to drive this one for another 50,000 to 100,000 miles, I would be replacing these parts at some future point any way you slice it.

Engine was lighting off as quickly as it did when new, hot or cold. No misses, no stumbles, slight degradation in fuel mileage.

All of the ground electrode platinum pads are gone. Gaps ranged from 0.056" to 0.068". Color is good (slightly off-white). This engine sees regular WOT exercise. Pictures available.

Speaks well of the OEM ACDelco plugs.

[JasonA]

Sounds good. I have almost 143,000 on mine, and I do plan to change them relatively soon (this summer probably). How did yours come out? Did you need an impact, or was a ratchet all you needed?

[JimD]

They came loose easily with a 21" torque wrench. Cold engine.

[sprucegoose]

Yup, I wouldn't wait too much longer... Besides, you'll be pleasantly surprised with the additional gas mileage with today's prices!

When I changed mine in the Goose at 152K I was thinking that they were already the second set, but who knows without any records. The platinum pads were gone on 2-3 of them if I remember right.

I think certain engines/ignition systems are harder on them too. My AC Delco plugs absolutely died on me at about 88k in my Tahoe with the 5.7L. I just put another set in this winter at 161K when I noticed it taking more cranking to start... They looked pretty bad.