I have 2004 S2000, only mods are exhaust and test pipe. Cylinder 4 is misfiring. It has oil where the coil pack was and in the cylinder so I took it to Evasive. They replaced ...

Replaced the coil pack
Replaced the valve cover gasket
Replaced the spark plug grommets
Valve adjustment
New Spark plugs OEM

And my car still misfires so I have no idea what to do. I'm open to suggestions thank you.

 

Take it back to the mechanic who "fixed" it and didn't. You paid for a repair what wasn't completed.

-- Chuck

 

Agreed.

Now, are you sure its the same cylinder misfiring? What if they fixed the issue you had at the time, then shortly afterwards a new problem occurred. Maybe the coil pack on another cylinder has now gone bad.

So that wouldn't be the mechanics fault (though personally I would have warned owner that of one part goes bad, the other three might not be far behind. Yeah, it had an obvious reason for failure, oil leak shorting it out. But still, if others failed soon after it makes my work look faulty if owner wasn't advised that migjt happen.)

Another possibility, is the heat cycled plastic harness clip that plugs in to coil pack has cracked, and now there is an intermittent electrical connection at the plug. All tbe coil packs were unplugged then replugged during the work, so that is definitely a possibility.

Fortunately you can just replace the plastic, and not have to cut wires or replace expensive harness. It requires a special tool to depin the wires from connector, so they can be plugged into new plastic clip. But with the tool its an easy 10 min job.

 

What was discovered during the valve adjustment?