Intermittent Code 41 Gremlin

[fixkick]

code 41 is ECU telling you the tachometer signal and the coil primary is dead. or weak or misfiring.
or bad wiring to the distributor.
yes the suppressor falling off will cause this. too.
a bad coil primary igniter too.
or bad spark coil, primary shorted.
yes old caps love to fail. they dry out inside and are bad, the one in the corner largest fail first
ok it is a 1990,
8valve engine.
when code 41 hits the ECU cuts spark so there can not be a fire. (crash and burn protection logic in the ECU)
so focus on spark only, ECU bad is last.
the 90 is not like the 91 at all.

the 90 has 2 things inside the that can fail
the VR sensor and the ignitor module inside. the VR has a gap spec too.
and the VR is known to fail or go intermittent or just the wires are bad.
its not the ECU its a bad dizzy or bad wires to it.
or the ground to it is bad.
schematic is here.

https://fixkick.com/INJECTORS/89/89-90schem1.jpg

good luck , I am kickfix.
the guts of VR are here
seen off here
https://fixkick.com/IGN_timing/89-timing.html

seen there id 6,7,8 are bad. or wires
the ECU is just saying the tacho single is dead or weak or intermittent.