I need the vacuum line schematics for 1992 Plymouth Sundance 2.5 engine

check voltage to battery with vehicle running it should be 14.25 volts .minimum 13.25volts. if voltage is not enough then voltage regulator ,and, or alternator is bad. make sure belt is not loose.

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Vacuum line to the heater controll box has a leak or is disconnected.

Or the controlls went bad.

www.ask.com/schematic/drawings/1992/plymouth/sundance/2.5/engine/vacuum/lines/

www.ask.com/1992/Plymouth/Sundance/2.5L/service-manual/
/troubleshooting-guide/
/wiring_diagrams/
/air-vent-layout/diagrams/
/door/diagrams/layouts/
/air-condition-layout-diagrams/
/ventilation diagrams/
/heat-duct-layouts-diagrams/
/what every you want or need/

possible a vacuum line is loose, pulled off below the dash going to the HEATER control system.

Being front wheel drive you might want to check the engine mounts. When your driving it ,the engine will move because of the torque. this is normal . If the mounts are bad it might be rattling or rubbing on something .

Code 51 = Oxygen sensor stuck in lean mixture mode. ( this will often cause engine to run rich due to oxygen sensor telling engine controller that it is running lean, thus send more fuel) This may be caused by M.A.P. sensor as well, so check vacuum lines and clean connections on MAP sensor first. It should be one of 2 things, Fault from MAP sensor, or faulty oxygen sensor.

front of the engine see picture below.

Unsure what engine or Vin Number is for your Car. All 0f the diagrams looked the same for the 2.2 - 2.5 and others, with and with out turbo.
Hope this helps, - Jarett