# Engine misfire but not code **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mazda\ **Created:** [May 18, 2023, 2:23am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684 "2023-05-18T02:23:38Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Saucedoroberto44\_182934](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Saucedoroberto44\_182934](https://community.cartalk.com/u/Saucedoroberto44_182934)\ **Post date:** [May 18, 2023, 2:23am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/1 "2023-05-18T02:23:38Z")
Is there a trick to know if a ignition coil is causing a misfire? My car is misfiring but not throwing a code. I don’t want to unplug while running because I’ve heard it could do some damage. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [May 18, 2023, 2:26am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/2 "2023-05-18T02:26:23Z")
If there’s no misfire code, there’s no misfire. Tester ---
**Author:** ![Saucedoroberto44\_182934](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Saucedoroberto44\_182934](https://community.cartalk.com/u/Saucedoroberto44_182934)\ **Post date:** [May 18, 2023, 2:32am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/3 "2023-05-18T02:32:43Z")
Yea I figured; was hoping it was simply a misfire. The car exhaust is releasing white smoke and hope it isn’t a head gasket. So could a head gasket cause the engine to run rough or misfire ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [May 18, 2023, 2:34am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/4 "2023-05-18T02:34:52Z")
> [@Saucedoroberto44\_182934](#): > > So could a head gasket cause the engine to run rough or misfire ![image](https://global.discourse-cdn.com/cartalk/original/3X/f/4/f414502a2e57c4f713469469d6447a56c9b0573d.jpeg) Tester ---
**Author:** ![Saucedoroberto44\_182934](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Saucedoroberto44\_182934](https://community.cartalk.com/u/Saucedoroberto44_182934)\ **Post date:** [May 18, 2023, 2:36am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/5 "2023-05-18T02:36:17Z")
☹ I guess it’s time to replace a head gasket ---
**Author:** ![asemaster](https://avatars.discourse-cdn.com/v4/letter/a/5f9b8f/32.png) [@asemaster](https://community.cartalk.com/u/asemaster)\ **Post date:** [May 18, 2023, 5:21am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/6 "2023-05-18T05:21:57Z")
What year and model is your Mazda? ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [May 18, 2023, 11:54am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/7 "2023-05-18T11:54:25Z")
> [@Saucedoroberto44\_182934](#): > > releasing white smoke Tester nailed it. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [May 18, 2023, 12:43pm UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/8 "2023-05-18T12:43:06Z")
> [@Saucedoroberto44\_182934](#): > > I guess it’s time to replace a head gasket Diagnose first, replace if that diagnosis shows a head gasket. There are products that can test for head gasket leaks. Like this: [https://www.amazon.com/dp/B08HKHJ6NY?psc=1&ref=ppx\_yo2ov\_dt\_b\_product\_details](https://www.amazon.com/dp/B08HKHJ6NY?psc=1&ref=ppx_yo2ov_dt_b_product_details) ---
**Author:** ![Saucedoroberto44\_182934](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Saucedoroberto44\_182934](https://community.cartalk.com/u/Saucedoroberto44_182934)\ **Post date:** [May 18, 2023, 9:51pm UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/9 "2023-05-18T21:51:29Z")
It’s much worse; I’ve checked the spark plugs and they have oil in them(just a little not soaking)and I checked the air filter and it has a lot of oil on it; now i think it’s the piston rings ![image](https://global.discourse-cdn.com/cartalk/original/3X/4/e/4e570918b0ca60f47283e028beee974010d2e2be.jpeg) ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [May 18, 2023, 9:55pm UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/10 "2023-05-18T21:55:40Z")
Have you checked if the PCV system is restricted? Tester ---
**Author:** ![Saucedoroberto44\_182934](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Saucedoroberto44\_182934](https://community.cartalk.com/u/Saucedoroberto44_182934)\ **Post date:** [May 18, 2023, 9:56pm UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/11 "2023-05-18T21:56:46Z")
No, I’ll check right now ---
**Author:** ![Saucedoroberto44\_182934](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Saucedoroberto44\_182934](https://community.cartalk.com/u/Saucedoroberto44_182934)\ **Post date:** [May 18, 2023, 9:57pm UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/12 "2023-05-18T21:57:38Z")
How do I check that? Do I just check the pcv valve ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [May 18, 2023, 10:08pm UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/13 "2023-05-18T22:08:49Z")
Oil on the spark plug tips? That could be good news, at least in relationship to the head gasket fault theory. When coolant leaks into the cylinders via a faulty head gasket, that often steam cleans the spark plugs. Some white smoke out the tailpipe is normal, especially in the first 5-10 minutes after starting a cold engine, & even longer when the ambient temperature is cooler than normal. There’s a few fairly easy owner-checks for a possible head gasket fault - the engine will be losing quite a bit of coolant, cup a week or more, but no leaks under the parked car - the amount of white smoke from the tailpipe w/ warm engine will dramatically increase when rapidly accelerating, like on a freeway on-ramp - there will often be visible bubbles coming to the top of the radiator (radiator cap removed) as engine idles, more so when increasing the idle rpm. ---
**Author:** ![Saucedoroberto44\_182934](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Saucedoroberto44\_182934](https://community.cartalk.com/u/Saucedoroberto44_182934)\ **Post date:** [May 18, 2023, 11:00pm UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/14 "2023-05-18T23:00:45Z")
I’ve checked the pcv and it rattles so I think it is the piston rings ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [May 20, 2023, 11:52am UTC](https://community.cartalk.com/t/engine-misfire-but-not-code/190684/15 "2023-05-20T11:52:38Z")
Time to run a compression test.