Miss or random miss fire

[Sammie77]

2018 cx5 driving down road between 40-60 it will kick & buck or it will go into limp mode , ck eng light on , it will say miss fire on cyl 4, 3, 2, 1 or just 1 of them or Random miss fire , but ive changed spark plugs & coil pack still same problem

 

[leeharvey418]

Do you have a rough idle condition? Any odd conditions when you change the oil?

 

[N7turbo]

2018 cx5 driving down road between 40-60 it will kick & buck or it will go into limp mode , ck eng light on , it will say miss fire on cyl 4, 3, 2, 1 or just 1 of them or Random miss fire , but ive changed spark plugs & coil pack still same problem

Did you change both plugs and coils at the same time? Many people have had problems with aftermarket coil packs. Seems only the OEM Mazda coil packs work reliably.

And make sure they are NGK Laser Iridium plugs.

 

[madar]

Dirty or clogged fuel injectors will also give you those codes. Try a few tanks with Techron fuel injector cleaner.

 

[Sammie77]

Did you change both plugs and coils at the same time? Many people have had problems with aftermarket coil packs. Seems only the OEM Mazda coil packs work reliably.

And make sure they are NGK Laser Iridium plugs.

Yes they are NGK Laser Iridium plugs & Yes I did this time Ordered the OEM Mazada coil packs , already ran into those problems haha thank you

 

[Sammie77]

Dirty or clogged fuel injectors will also give you those codes. Try a few tanks with Techron fuel injector cleaner.

 

[Sammie77]

Ok I will try that thank you

Do you have a rough idle condition? Any odd conditions when you change the oil?

No

 

[Sammie77]

Dirty or clogged fuel injectors will also give you those codes. Try a few tanks with Techron fuel injector cleaner.

Ok I'll try that thank you

 

[GFrosty]

Ok I'll try that thank you

A few months back, I had several weeks of rough idle, low idle. Wasn't always, but most days. It was about time for the plugs, so put in a new set. And testing of the coil packs showed results weren't perfect, so replaced those.

Additionally, I have done the Chevron Techron thing. Have now done 4 tanks of adding a bottle at the fill-up. And now all the P0300 random misfire codes are gone. Car's running smoother. And fuel efficiency has gone up a couple mpg ... same roads, same basic driving habits, same basic percentage of city/hwy driving.

While it could be a sensor, it's quite likely your plugs+coils+Techron will have good results. I wouldn't expect a single bottle to do it, alone, but two or three tanks' worth ought to see improvement.

At nearly 130Kmi, this autumn I'll be doing a full engine bay cleaning and going through a variety of the sensors to clean them and ensure all's well.