# Same cylinder ignition coil **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [December 5, 2019, 11:39am UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093 "2019-12-05T11:39:27Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![dan.spaeth\_160577](https://avatars.discourse-cdn.com/v4/letter/d/5f8ce5/32.png) [@dan.spaeth\_160577](https://community.cartalk.com/u/dan.spaeth_160577)\ **Post date:** [December 5, 2019, 11:39am UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/1 "2019-12-05T11:39:27Z")
Looking for some insight before throwing more parts at the problem. 2007 Mitsubishi Endeavor. 190k miles. Misfire on Cylinder 4. Swapped coil with cylinder 2 and confirmed misfire moved to cylinder 2. Bought a used coil from junkyard (60k miles). Put it in cylinder 4. Car runs great. Replaced all 6 spark plugs with new NGK iridium. Confirmed all plugs were correct gap out of the box. After about 20 miles of driving, cylinder 4 starts misfiring again. Swap coil. Code moves. Looks like I killed another ignition coil. Did I just get a bad coil or is there something going on that could be damaging the number 4 coil specifically? Computer problem? ---
**Author:** ![tcmichnorth](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tcmichnorth/32/25126_2.png) [@tcmichnorth](https://community.cartalk.com/u/tcmichnorth)\ **Post date:** [December 5, 2019, 12:44pm UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/2 "2019-12-05T12:44:55Z")
Replacing a coil with one from a scrap yard is like replacing a light bulb that burned out after 1 year with a used 1 year old light bulb. ---
**Author:** ![dan.spaeth\_160577](https://avatars.discourse-cdn.com/v4/letter/d/5f8ce5/32.png) [@dan.spaeth\_160577](https://community.cartalk.com/u/dan.spaeth_160577)\ **Post date:** [December 5, 2019, 2:07pm UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/3 "2019-12-05T14:07:47Z")
Agreed. It’s not ideal but I’d expect it to last longer than a day right? ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [December 5, 2019, 2:11pm UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/4 "2019-12-05T14:11:43Z")
> [@dan.spaeth\_160577](#): > > ’s not ideal but I’d expect it to last longer than a day right? No, used parts have a life expectancy of 1 minute to who knows how long. ---
**Author:** ![old\_mopar\_guy](https://avatars.discourse-cdn.com/v4/letter/o/6bbea6/32.png) [@old\_mopar\_guy](https://community.cartalk.com/u/old_mopar_guy)\ **Post date:** [December 5, 2019, 2:25pm UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/5 "2019-12-05T14:25:45Z")
Buying a used coil is like buying used underwear. Yuck. ---
**Author:** ![eddo](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/eddo/32/2594_2.png) [@eddo](https://community.cartalk.com/u/eddo)\ **Post date:** [December 5, 2019, 4:22pm UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/6 "2019-12-05T16:22:32Z")
> [@dan.spaeth\_160577](#): > > Agreed. It’s not ideal but I’d expect it to last longer than a day right? be happy that you got 20 miles out of a used coil and go buy a new one. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [December 5, 2019, 6:52pm UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/7 "2019-12-05T18:52:59Z")
With the plugs out on a 190k miles engine I would strongly suggest a compression check. A cylinder that is dropping compression can lead to subtle plug misfires which can kill a coil… ---
**Author:** ![dan.spaeth\_160577](https://avatars.discourse-cdn.com/v4/letter/d/5f8ce5/32.png) [@dan.spaeth\_160577](https://community.cartalk.com/u/dan.spaeth_160577)\ **Post date:** [December 6, 2019, 11:57am UTC](https://community.cartalk.com/t/same-cylinder-ignition-coil/154093/8 "2019-12-06T11:57:57Z")
Alright, well after the public shaming over buying a used coil, I broke down and bought a NEW coil. Installed it yesterday in Cylinder 4. It survived the commute home yesterday. Hopefully it’ll hold up. I will say that the new boot fits much tighter over the plug. I’m thinking electrically that used coil was probably fine but with age the boots probably shrink/dry and no longer insulate properly (best guess). Maybe it’s less about miles and more just time. Thanks for the suggestion on compression testing. I should have done that when I had the intake off. I’m planning on changing the timing belt over the Christmas break. Maybe I’ll do compression test first though.