Spark Plugs? Iridium vs. Platinum
 

I've looked over this forum and haven't seen anything posted for plugs: Iridium vs. Platinum. I'm planning on replacing the wires and plugs soon in hopes of getting rid of a very slight miss. I know some vehicles call for iridium spark plugs specifically, and have noticed a fuel economy increase when using iridium (vs. platinum) plugs.

My question: Are the Iridium plugs too hot to use in the 5.7L ('97 Burb)? The platinum and the Iridium plugs cost about the same. Has anyone seen a fuel economy increase (however slight) when using Iridium plugs?

I don't think the iridium plugs will cause problems, but I thought I'd ask to see if I've missed something.

Thanks again!

My understanding is that the only difference is that the iridium is harder/more durable than platinum. I had NGK iridium plugs in my 01 Burb for 85,000 miles with no issues.

Every time the spark jumps across the electrodes, it takes a small bit of the metal with it. Over time, the gap opens up, leading to decreased performance. 35,000 volts causes the same arc/spark whether it's copper, steel, platinum or iridium.

From what others have said in the past, you're best to stick with the specified AC Delco plug for your vehicle.

Other than the dealership, does anyone have a good resource for listing OEM equipment? I'm leaning towards the AC Delco plugs (since they cost the same as the Autolite). However, AC Delco makes the platinum, double platinum and the Iridium for my truck. I'm leaning towards the standard platinum (with a good coating of anti-seize on the threads!).

The owners manual used to list the required spark plug. If it doesn't, check with local auto parts stores.

Be sure to check Amazon, the ones I need are are the same price as they are here locally, however I can get them delivered for free and some items are tax free via Amazon...

Thanks for the ideas. The local parts store lists the copper, platinum, double platinum, and iridium. Even though copper is the best conductor, it doesn't last as long as platinum or iridium, so I'm avoiding copper. I'll have to check out Amazon. Sometimes I forget that Amazon has the specific auto parts that I need, despite having ordered auto parts from there before AND having a Prime account.