spark plug gap??

[internic]

did chevy for certain change the stock plug gap from .060 to .040? i've heard it over and over but i want to verify. I regapped my champion platinums to .045 (were .060) and it seems to have more power. cant tell if mileage got better or worse yet.

[internic]

ok never mind, i regapped them to 60 thousandths. they changed the stock gap to 40 but also to iridium and both of those facilitated other changes too ie engine and coils, so it would be foolish to change a pre-.040 engine to .040

this was partly educated guess but also cause i went to the chevy dealer and went into the service bay and asked a mechanic about it and he yelled at me for using a 40 gap on my 1999 and told me to change it back lol

[rjirvine]

I was under the impression that the original platinum plugs were .060 and the new "stock" plug is the iridium p/n 41-985 which is gapped to .040. I'm not sure if you have to have the PCM changed, but from what I've read, the smaller gap is an improvement. Do I have it right?

2000 silverado extended cab, 5.3, 4x4

[silveradoman]

I regapped mine to 0.050 and the O2 sensor was reading lean almost a day until it compensated, so I did get a better combustion out of it...

[kenny-1907]

When i had my Silverado at GM for a rough idle issue the Tech there told me that when someone brings in a truck for a tune up that they no longer use the .60 gap even if they still have stock left of the old platnium plugs. He told me that the larger gap was to help aid in a quicker start in colder climates and for improved fuel mileage but it was also causing alot of problems because of the higher resistance needed to make the spark jump the larger gap.