On mine when it started having issues I replaced:

-Wires
-Spark plugs
-Rotor
-Cap
-Coil
-ICV
-Air Pot sensor
-Injection temp sensor
-Air intake sensor (yours being an 88 does not have this)
-EHA valve (it was leaking too)
-Made tiny adjustment to fuel mixture to richen it
-Air filter
-Fuel filter
-OVP relay

Tested micro switch on throttle to be working properly otherwise I'd have done that too.

Ever since its been running great!

__________________
-diesel is not just a fuel, its a way of life-
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