I will be driving down the road and the jeep will start chugging and backfiring and smell rich.I just keep my foot on the gas and eventually it will go away for awhile then starts again.I have replaced plugwires,fuel pressure regulator ,fuel filter,module in distributor, still does it.Thishas been happening since last july and is getting worse.Anyone else ever have this problem?Check engine light does come on before it happens.