I have a Check Engine light on and diagnosed a P0300 code. I finally got around to testing my coils and need some help telling if the packs are bad.

Pack 1 (1/4)
Secondary 5.56 K ohm
Primary 1.0-1.2 ohm

Pack 2 (2/5)
Secondary 5.73 K ohm
Primary 1.3-1.5 ohm

Pack 3 (3/6)
Secondary 5.48 ohm
Primary 0.8 ohm

Are packs one and two bad? Would these readings explain the code and stuttering during acceleration in the 2k-3k RPM range.

Thanks

MAybe not the best way but with each of the posts, maybe just pull the wire off the plug, place it close to metal [NOT near any of the gas lines or sensors] and see if it is sparking. You will see and hear it. Don't run like that long tho.

I once had the 1/4 go bad and the 1 would not spark at all. Mine was easy tho cause it was rusted so the problem was evident before I ever started.

Well, looking at this Tecninfo article Ignition coil troubleshooting , it looks like they might be bad. The primaries are out of spec a bit.

Will Autozone test them?

I wouldn't trust AutoZone with a piece of paper. Double and triple check them before determining they are bad. If you want someone else to test them, find a good auto shop and have them do it.

The primary on the first coil is marginal, the primary on the second coil is out of spec (.05 - .09 ohm)

You could try some junkyard coils that test within spec without spending a lot of dough.

Could also be bad plugs or wires.

Thanks for the advice. I replaced the plugs and wires in the summer, so I don't think that'* it. I'll pull a coil from the Buick and see how it tests.

As for parts, is Autozone out too? They list a coil pack for around 25 bucks.

I got an entire ign set up with module and 3 coils i matched myself for $20 from the u-pull-it. I even got an extra set on my shelf. PM me if you need a coil.

They are not out of 'spec'. The Techinfo article is just an average of half a dozen coils of each type.

You will never notice a difference in performance with those numbers. Not perfectly matched, and not super-ideal, but not bad either.

For P0300, clean the posts on the coils, check the resistance of the wires while a friend gently bends and lightly twists them, inspect all 6 plugs to see if it'* isolated to one or two.

If a coil were bad, it would take out two cylinders. If a post is corroded, it could be a random on one. Make sure your #5 and 6 wires aren't touching the O2 harness, and make sure no wires are arcing to ground. The best way to check that is to lightly mist the engine with water (windex bottle) at night while you idle with the lights off.

I seriously doubt the coils themselves are your problem. They are an on/off device.

Thanks for the correction, willwren. I learn something new every day.