Our 2001 Rav4 started going through coil packs about every 12K. I noticed that the spark plugs had worn down to thin metal and also needed replacement. Wondering what is driving this failure? Saw some old posts about perhaps ECM causing this or bad coil pack ground? I'm also aware the ECM on these has a flaw that can manifest itself as transmission problems and wonder if there is any relationship to a bad ECM? Appreciate any thoughts. Thank you.