1998 Neon Rough Idle/trouble code p172

Ok, so I recently discovered that my 98 5spd neon was running a little rough, it sounds like its cammed when it sits at idle and if i'm traveling and push the clutch in the rpms drop to 500 for a second or two and then come back up to 950-1000 and idle rough in that position. I have already changed plugs, wires, fuel filter, and fuel regulator. The engine also threw a trouble code p172 (too rich bank 1). Any help on this would be great....she gets me back and forth to school and i cant afford to be driving a dying car!

checked fuel pressure, engine compression.....without a scanner it's hard, a quick scan of the sensor voltages will tell you a lot