jdsSC

I hopped in my car yesterday to find my SC4 running like an SC2. I've read all over the forums and the common consensus for this symptom appears to be bad coil packs or plugged cats. It didn't happen slowly, ran fine in the morning taking the kids to school then first fire in the afternoon it seems like it's running on 4 cyls. Rough idle, tach is jumping all over the place and sometimes settles at zero for a second or two before responding again, pathetic accel, etc. I pulled both packs and measured resistance and have nearly identical findings. Comparing the results to the owners manual it appears both coils are bad but how common is this? I don't want to replace coils if they're not bad, that's $100+ that can go to fixing whatever the problem is if the packs are not the issue. I'm not sure of the age of the packs, but the car has 221k on it. They are both factory Toyota Denso coils but the car's first 100k of its life saw regular service at the Lexus dealer. From 100k-220k I have only regular service records with nothing showing coil replacement. So it's possible they do have 221k on them or maybe 120k or less. My readings on the 2 coils are .8 and .9 (measuring the contacts circled blue) and 12.75 and 12.44 (circled red and also measured the other prong not circled red against the main - same results). The 12's appear to be in spec no problem, but the readings of .8 and .9 are way out of spec if I'm measuing this right. If not, please let me know but the manual says .4-.5 is spec on the primary. Thanks in advance for any help or advice you can give.

jdsSC

Slight update, sort of....I took them into the local auto parts store and a pair were ordered and will be in on Saturday. They said I can check the resistance of the new pair compared to mine before I purchase them to verify the readings are off since they can't be returned being an electrical item. One of the clerks said it's odd to see both go at once but not the first time. Lifetime warranty on them for $54 a piece, not bad if it turns out to be the coils. I'm hoping it is and not something else because that means back to the drawing board of the several other issues that could cause this.