420A 1999 Mitsubishi Eclipse 420a cylinder 1 misfire

[Pjose258]

Hi I'm new the the DSM community. I recently bought a 2g Eclipse and was able to get 99 percent of the issues resolved. But I keep getting this random cylinder 1 misfire.

I have already replaced spark plug wires, spark plugs, coil pack, injectors and all vacuum hose. I am completely out of ideas besides maybe a fuel pump or filter but its only the cylinder 1 that keeps misfiring. I was wondering if anyone else has had this issue.

The misfire is random sometimes it happens almost immediately after turning on the car, other times it can go 30 miles without misfiring. PLEASE HELP

 

[BLACK'98DSM]

Have you tested compression yet?

 

[Pjose258]

No thats another thing I haven't tested. I figured it was fine because its very inconsistent when it misfire. I am noticing a ton of carbon buildup in my intake and exhaust manifold so im gonna try cleaning them.

 

[Pjose258]

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So I found this today when bore scoping the internals, not sure why its staying open but im assuming I need new valves?valves? And whats the building up on most of my valves is it carbon?

 

[97egl]

The carbon build up you have there is perfectly normal for a higher mileage engine. The valve looks closed to me. They don't sit down inside the head they sit against the valve seat which is flush with the head.

Do a compression test

 

[Pjose258]

I have my compression tester coming in today but no I checked all other valves in the block and found this one is definitely staying open. I'll try and take better pictures but the back section is the open part of the valve.