car kicking

My friend owns a 2000 eclipse gt and it has a problem. When he's driving around the car will kick at certain times, like we will be driving and it will kinda stall out for a second and then be normal. I think it's a sparkplug misfire, but I'm not sure. We have changed the sparkplugs and the leads and we have removed the exhaust manifold and reseated it and it fixed the problem for a couple days but after that it just came back. I can't think of what it could be. Anyone have any ideas or had this problem before? The only other thing I can think of is the injectors maybe.

were the sparkplugs gapped correctly?

were the sparkplugs gapped correctly?


They were pre-gapped. We hooked the car up to a diagnostic and it just aid #number 4 cylinder misfiring, and we removed the sparkplug and reinstalled it. I know everything is in there right.

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