I have a 91 yj jeep 2.5 engine.The jeep cranks up fine and idles fine .When changing gears and rpm up no promblem but once it levels out it start to sputter at a steady driving speed.If i give it some gas the sputtering stops but once it gets at steady rpm it starts sputtering again. It does this in all the gears.Any HELP on what to look for Thanks Brian.