Spark plug change now engine misfire

[AnalStick]

So i just changed my sparkplugs on my r34 everything was fine I drove it for like 10 minutes and then the engine light came on and then it started misfiring really bad, now on idle, it sounds like its running on fewer cylinders. I got engine fault code 21

[HCR32 type M]

Did you re-gap the spark plugs before installing them?

 

[AnalStick]

7 minutes ago, HCR32 type M said:

Did you re-gap the spark plugs before installing them?

 

So I took the old ones out and I checked them all and they were the same