In my opinion you can not beat the oem Ac Delco iridium plugs.
I have ran in to problems with most all other plugs in these.
The 2004 GMC Savana has a V6 engine.
The 2004 GMC Yukon has a V8 engine.
Where are the freeze plugs located on a 2003 GMC Sonoma 4.3L Vortec engine?
The 2004 GMC Canyon has an inline 4 engine.
The 2004 GMC Yukon-XL has a V8 engine.
The 2004 GMC Savana-Cargo has a V6 engine.
The 2004 GMC Sierra-2500HD has a V8 engine.
The 2004 GMC Sierra-1500 has a V6 engine.
Plugged catalytic converter? Air/Fuel filter? Worn plugs?
6
The 2004 GMC Savana has a 4.3 L base engine size.
The 2004 GMC Yukon has a 4.8 L base engine size.