2003 H2 Question

[mdoyle]

I've got a 2003 also and based on past experience I always stick with the AC Delco OEM plugs from the dealer. On another truck (Chevy Duallie) I tried the Bosch Platnium and there was a noticable reduction in power.

Years ago I ran a car at the strip and we would swap out plugs for different heat ranges and read the insulators as part of our tuning along with jet changes, ect. The main thing I learned through that process is that different plugs will make a very measurable difference in performance.

[IRA51]

the right heat range NGK plugs will be as good as the AC delco plugs.if the idle is going up and down I would take a hard look at your mass air sensor,they can be bad and not throw a code. I wouldnt hurt to decarb the engine and clean the throttlebody also.

[Adam in CO]

Mine does that in the cold.