[HWYSTR455]

I have had 1 Blaster II and 3 Blaster SS coils go on me in a row, all around the 5-10k mile range.

My symptoms were that it ran fine for about 45 min, then it would slowly start dropping of performance from higher RPM to lower RPM, and then finally die.

It would start out as a high RPM miss, then it would continue, happening at 500 RPM less, then another 500 RPM, all the way down until it would die and not start. Each step it wouldn't go beyond the RPM the issue was at.

I even tried going to an HEI dizzy in troubleshooting that, coil in cap, and went through a few coils there.

Not sure if it was a MSD box issue or alt issue, but along the way of troubleshooting those were replaced, but after I went to a different E-core coil it all finally went away.

Now I run the Hyperspark coil, which is the potted type with a heat sink. Fingers crossed.

One tell-tale sign was as it would start missing/breaking up/RPM limited, the coils would be hot to the touch. And I mean like you could hold you hand on them at all. But I wouldn't use that as an indicator, a coil still could be bad in that case.

Valve spring. They should last to 100k miles or more. They may lose some psi, but doubt it would prevent RPM from going over 4000. Time too can add to the degrading life of springs, but each case is different, so you can say X years for all spring.

But just to say, a replace-coil test is an inexpensive test, and chances are you will be able to use the new coil as a spare or on another project.

Just like valve springs, plug wires go bad too. If they are over 5 years old, it's a good idea to replace them. Not saying that's the issue here, but if you're troubleshooting, you could scratch that off the process of elimination list.

Make sure you do the wire from coil to cap too.

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