Other half's celica was running a bit rough. Coming up due the 40K mile plug change (iridiums are OEM) - pop them out to change - copper, and the wrong heat range. Burned down to a gap of about 2.1mm (should be 1.1). No wonder it was stumbling a bit and the economy was dropping!

I'm not a fan of dealer servicing either, they charge too much and do the bare minimum. Do what you can yourself and use a decent independent for the bits you can't.