I've had repeated problems with my 2001 V6 on-plug coils. Does anyone know what the resistance should be on a coil? or how to test them? In the past I have just replaced them all but it's too dang expensive!!!!!!!!!!! I just want to find the bad one(s). Don't say get a new one and keep swapping it out till you find the bad one!!! They only open when the engine is at operating temp. Thanks T