1991 Jeep Wrangler I need help.

My jeep is missing and sputtering at idle, the trans was replaced not too long ago, spark pugs, wires, fuel filter, fuel injector cleaner ran through it, seafoam ran though it, cleaned the throttle body, adnn soon im replacing the head gasket. Im all outr of ideas as to whats causeing this. Jeeps are known as creepers you can get out and walk along side it and itll keep going. Mine stalled itself today doing just that, and right now its lighter than normal no hardtop or doors