Coil resistance will change a LOT with heat- it's a very long length of fine wire in there. The resistance is rated in ohms per foot, and the change due to temps is in ohms per foot per degree C- and you've got a lot of feet in there. So it's not surprising to me to see very significant resistance changes with temperature.

I used to build small magnet coils for a company, and the resistance of those would change wildly with temperature- they were the size of your thumb and constructed of like 36 or 40AWG wire- very very fine. A thousand turns of wire in a tiny coil. Really a miniature version of the ignition coil.

In any case, I'd guess the coil is fine because it does show *some* value. It's not open-circuit and not shorted out. Have you measured 12V at its terminals with the key on? Do you get a pulse on one terminal when cranking?

And last, I'd try the coil in another car, or another coil in your car. They ought to be a cheap junkyard part. Pretty much any aftermarket one, like the coils for air-cooled VW's, will work too. At least it will work for a test.

Good luck with it!
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Rob Bareiss, New London CT ::: 92 244-M47-208K ::: 90 745GL-M47-271K ::: 88 245DL-AW70-182K ::: 84 242 project ::: 70 VW Bus ::: 70 Bus SInglecab Pickup ::: 71 VW Type III Notchback