Awesome.

So you only bought the coil pack which came with the boots and ICM?

 

2003 Saturn ION 2 automatic with 2.2 hamsters and 148,718 miles (February 2025)

Correct, the NGK was a complete assembly that included the coils, the ICM, boots, and even a serving squeeze pack of plug sauce for $154 (3 year warranty)

The $94 option was just the bare coil assembly. I asked of the boots and they were $9 each (and this chinesium part had only but a 1 year warranty ), then at final glance I noticed it also didn't have the ICM.

Question (s):
It seems to me like the coils are likely robust, is it the ICM's that are likely to fail?
Might it have been likely that just changing the ICM (could) have fixed it? [ for my future enrichment / reference ]
Is there any field test of the ICM or will the fault codes specifically indicate it? (other than misfire reported)

 

Many more coil failures on the ion reported on this forum than actual ICM failures. So that means people that want to figure it out themselves end up finding more coil pack failures. Can't truly generalize it across the board because we don't know what happens with all the people that never come to the forum, But that's what we've seen.

With old cars and old wiring, there's always a chance a marginal connection is no longer a marginal connection somewhere somehow. Only boy changing one thing at a time Will you ever get the answer to your own question. Changing two variables at once makes it mathematically impossible let alone logically impossible to determine which change in variable led to a change in behavior.

Sometimes we care, sometimes we don't care.

Most of the time we care because we don't want to throw extra dollars, extra parts, and extra complexity into a repair that doesn't require it. But with the much smaller choice of available parts, sometimes you need to do what you did which is get what's available.

We just try to steer people towards sound troubleshooting techniques which in turn saves them money that would otherwise be thrown at parts for lack of knowing whether they are the problem or not.

 

* 2003 Saturn ION 2 automatic with 2.2 hamsters and 148,718 miles (February 2025)

Perhaps the varies resistance of the 'other than OEM' sparkplugs can tax the coils...
I know on some other wasted spark coil packs, that if the recommended sparkplug change is not observed and as the spark plug gap enlarges, the greater airgap is also increase in resistance.
It had been proposed that this neglect will cause a coil pack to 'wear out'...
I suppose that theory could hold some merit.

*2003 Saturn ION 2 automatic with 2.2 hamsters and 148,718 miles (February 2025)

 

As the gap widens, it takes a higher voltage potential across the gap to create a spark. I don't know that I would call that electrical resistance because I think it's really impedance, not just the resistance. Blah blah blah boring not wasting anyone's time with that explanation