Some of you may have been planning to change your spark plugs and give the Delco Iridiums a try. I decided to go for it today and was pleasantly surprised to see a $2.00 per plug rebate on my AutoZone receipt. That knocks the cost down to $4.99 each. Looks like a good time to go ahead and plan that spring tune up!

 

Let us know when you install them how the motor behaves... Are they direct replacement OEM?

 

Yeah Dan, they are direct replacement. There are several reviews here on the site that all sounded pretty positive to me. From what I have read, later H2s and H3 Alphas use iridium plugs from the factory. I am not sure on that but it is just what I have read here on the forum. I just hit 94,000 miles and as far as I know am on original plugs. I'll let you know how it turns out.

 

Did a little cleaning on the TB yesterday, and changed the plugs today. Haven't really had a change to drive much. Not a big change that I could tell on the short trip. I read something about 'relearning'. Don't know how long it takes for changes to show up. The existing plugs were iridium, same as the ones I put in. I mentioned above that I had read that some Hummers came with them from the factory. Not sure if mine did or not but they appeared to have been in there a while. The tip was quite a bit worn down.

 

My idle is going between 660 and 690. Those are extremes. Usually sits around 675-680. I don't have a clue what the throttle % should be, or the vacuum.

I took a very short 5 mile trip to the post office and back. The average MPG as reported through the ECU was 20.1. I know it won't stay that way but it made me feel good for a minute.

And I have always been very impressed with the cooling of this truck. Been sitting in my garage idling for at least 20 minutes and the temp is still just at 181.