rough idle and black soot in #4 cyl after head gasket change

[ixcocoyxi]

as the title says, my car has a rough idle when started and there's black soot on my #4 spark plug. when i first pulled them out, they were fine all the same gray/white color.

new intake manifold gasket
new head gasket
new spark plugs (because i noticed the black soot after the first test drive)
timing is good

i didn't disconnect much in the intake. just a few hoses that connect to the head from what i remember.

my air/fuel gauge, the light is pretty much spread out thru the entire gauge when i went for a test drive. at 4500rmp, it bogs and backfires like crazy!

i haven't changed anything else.

 

[R13]

Did you do a compression test to make sure your headgasket's still sealed good?

 

[ixcocoyxi]

Did you do a compression test to make sure your headgasket's still sealed good?

not yet. but would that lead to it misfiring?

 

[R13]

Think about what you just said for a minute :lol: :lol: :lol:

 

[ixcocoyxi]

Think about what you just said for a minute :lol: :lol: :lol:

I'm just saying because i already know i have low compression on all cylinders :lol:

 

[R13]

:lol:

In that case yeah, you could have a minor leak and it could cause that.

Check your coolant too, see if it looks contaminated. Shine a light in it to see if there’s any visible carbon in it.

 

[ixcocoyxi]

:lol:

In that case yeah, you could have a minor leak and it could cause that.

Check your coolant too, see if it looks contaminated. Shine a light in it to see if there’s any visible carbon in it.

will do. most likely this weekend. I'll post up results.

 

[R13]

:thumbs up

Hopefully that’s not the issue, but that’s the easiest variable to diagnose, so it’s best to start there.