1991 240sx: What are the symptoms of a dying Distributor?

[grachman]

these are my symptoms:
-car sounds like the muffler is going. I guess it is missing . has been doing this for at least 5 months.
-rich at idle
-car started showing the code for speed sensor about a month ago(speedometer works)
-car is now hard to start in cold or hot conditions. disconnecting battery seems to help. I'm getting code21 now-primary ignition signal circuit fault
-car recently died while driving. restarted after disconnecting battery cable.
-replaced ignition module and ignition coil

Are used distributors worth it. They sell for $200 in my area. $400 for a remanufactured one.

[ATLspeed]

i need to know this as well

[grachman]

My code 21 and dying/no start was caused by loose connection where ecu plugs into harness. It was a new computer that did not plug in snugly. Put my old computer in and it solved the problem.