I tried here:

https://listado.mercadolibre.com.mx/1992-ramcharger-manual-de-servicio#D[A:1992ramchargermanualdeservicio]

nada

What I recall is they didn't sell the mexican vehicles here because of emissions and safety standards. However I think an O2 sensor is de rigor with a TBI system? It seems I recall seeing one in the US long ago w/ a rear wiper? Has yours got one?