motor stumbles after it warms up

[fixkick]

1985 engines. F code engine
is that
so that is G13F a G13, with wrong TBI and wrong, ECU.
and is a sammi engine, with I guess a orig. sammi 8v G13 head. (or with newest G13 head, with newest distributor, the DIZZY has pn/ on the side that i can tell you what it came off of)ask.
but must have TBI off what? last years sammi up to 95 or manifold off G16 TBI 89-95? sidekicks or trackers??

ECU is for sure G16 and is TBI and we know 89/90 Sidekick or Tracker, its for sure not off any SAMMI
Since the harness at ECU is wrong, Ive no clue what it can be..
the first 89s, were made in iwata, then the production (usa./canada) moved to CAMI canada., some changes happened then , no idea what. (lots of parts are now usa./canada made)
in fact mine was painted in GM chevy corvette red, day 1. in CAMI.

some have the fuse box diag fuse
others do not, depends on GEO/SUZ name and year,
there no years with the harness to ECU missing a15 pin, never seen it or heard it ever.

I bet your car has harness issues, seems so...
I think the ECU that is mapped (AIR ?FUEL) tables, my have great difficulty using, 300cc LESS displacement.
id have used a 1995 Sammuri, ecu on a G13, engine. so the fuel tables match.
idle will work i bet.
but driving, car, the vacuum readings will not match 1.6L , so all map readings are wrong to the ECU. causing Chaos.
if the car had a maf sensor this would work.
like we do mixing J18./20 engines, and ECU.
but MAP engines, are very fussy on vacuum, "Speed density "systems ALL ARE THAT. for sure accelerating it will get confused,

the ecu needs to match engine in car, for sure displacement. (TBI)