90 eclipse intake port question

[90EclipsePos]

Any help would be great. I have a 90 eclipse that I have been building for a while with a lot of issues. Ever since i rebuilt the engine It would not idle right. The first issue I found was that the rebuilt head I purchased had the cam and cam gear from a newer evo. So I thought for sure that the valves would have been bent so I tore the head off and fluid tested the valves. All valves sealed perfectly with no leaks, but I noticed that one of the intake ports looks almost new compared to the other 3. Also the piston for that cylinder is cleaner then the rest. It still has some build up on it but not as much as the others. Any ideas what could be happening?

Thanks

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[Talyn]

Check fuel and spark on that cylinder. usually when you have a cylinder thats inexplicably cleaner than the others its bc there isn't any, or isn't good combustion. Although I suppose a coolant leak could possibly cause that as well if it were leaking coolant into the cylinder, as it essentially steam cleans everything when burned, but then you would probably have smoke.