Hello, I am in need of advice! My car's ignition coil failed a year and a half ago and was replaced. A few week's ago I started having the same misfiring problems, plus check engine light on and cruise control light flickering, took it to a different mechanic (my regular mechanic), who did a bunch of stuff that didn't fix the problem. So then I took it back to the first mechanic, who told me that the coil they put in failed, and they replaced it with free labor, but charged me for the new part from a different manufacturer. I asked if the catalytic converter was damaged and they said no, those are hardy and will be fine. Now the car is firing correctly it seems (full power, no shaking/stalling), but the check engine light came back on and the cruise is flickering (which always starts simultaneously). Took it back to the shop and they say it needs a new cat and maybe new O2 sensors ($700-$1300 total), but that this is unrelated to the misfiring, as is the cruise flashing. It's obviously ridiculous for them to tell me the cat dying right now is just a coincidence. And what about the cruise flashing? Does anyone have any ideas for what might be going on? And shouldn't they be more responsible for paying for all of this extra damage from their having put in a bum part in the first place? Any help is appreciated.