Spark Plugs
 

Iridium Spark Plugs

Iridium is a precious, silver-white metal and one of the densest materials found on earth. The natural properties of Iridium offered the opportunity to create one of the world's finest spark plugs. The result are spark plugs that require less voltage to spark, burns fuel more efficiently, sparks at leaner air/fuel mixtures, and delivers higher horsepower and better gas mileage.

ok, ok.

But why does the decal on the engine scream at me:

USE IRIDIUM SPARK PLUGS ONLY

My guess is that the engine was designed to the limits of what was street legal, and by changing the type of plugs, the vehicle would no longer meet emissions.

-Jay

What's the make and model of car?

It could be that the car manufacturer and spark plug manufacturer entered a contract- something like "We'll give you a good deal on sparkplugs for your new cars if you put a sticker under the hood that will get ppl to buy our replacements..."

4.7 Tundra.

or if you read your own post its because they require less spark power hence your ignition system might not produce a high enough spark with regular copper core/platnum plugs.

or it could be the contract deal thing between companies (wouldnt be supprised if it were)

...or that they are long lasting and help keep their emissions good until out of warranty?

Probably for the finality of CAFE standards. Similar to the reason why 5W20 oils have entered into manufacturers' requirements.

Also, with "less voltage to spark", that would reduce the power necessary to operate the ignition system...or that a smaller amount has been relegated to it. Just like using HID's by manufacturers reduces power to produce light.

Profitiability too? If the margin is 10% on a set a plugs, you make more selling an $8 plug when compared to a $4 plug.

Profit margins in the parts department are a lot more than 10%. Try 30% - 40% at least. When I bought my new tires over the summer I went to my brother in law's dealer (He was the manager of the service dept). I got the tires for cost + 10% (That dealer's standard employee/family rate) which turned out to be a savings of ~$70/ea.

-Jay

I'm just illustrating, I'm sure you recognize that. There are many times when there is 100% mark up from cost to retail in parts markets.

I used to have a Jacobs Pro Street Electronic Ignition on the Dakota.

The way it worked was to sense resistence as the plug fired. Each time a plug fired the computer did that and so it was possible to have sparks of entirely different duration, strength and number of them, each power cycle of each cylinder.
Fast thinking, but it was at light-speed.

Anyway, it worked and the Dakota did in fact have better gas mileage as a result and the savings paid for it in around a year because I am a Courier and drive a lot, but, I digress.

So, I am wondering about this Toyota.
The first thing I wonder is if, maybe, the reason it takes a long time cranking before it starts is to let some oil get pumped before the ignition is turned on?
I also wonder if the 'Coil-Pak' ignition is set up to work the way the Jacobs did?
Why not?