inferno s14

i read crazy threads and they all had nice info regarding my problems but i tried mostly everything and nothing.

Basically at idle my rpm's drop (750 to 400) sometimes lower and during that i have black smoke coming out the exhaust and the smell of gas just basks in the cabin. It only does this at idle and when the car is at normal temp. I could see my speedometer lights dim when the rpms drop.

MOTOR RUNS REALLY STRONG AND PULLS HARD FOR A 1991.

background on the car:
1991 240 hatchy, cars completely stock autosatan, abs leather package. when i got the car the positive cable was cut, so i ghetto rigged a wire to the battery and wrapped it in electrical tape ( BEEN HOLDING mE DOWN FOR THE LAST 3 MONTHS).
-changed maf
-using cheap autozone plug wires
-replaced all fuses
-changed dizzy cap
-new ngk's
-new air/fuel/oil filter
-cleaned all grounds on engine bay
-swapped fuel rail/injectors from another 240
-checked timing and its on point
-replaced cts with new one
-new bosch o2 sensor
-duralast gold battery



now i heard about clean the Iacv but would that cause the motor to run rich and spit out black smoke at idle? i wanna clean it anyway when i pull out the intake manifold.

i also heard TPS but my throttle response is on point and have no type of hesitation throughout my rpms, so same question as above?

MAF? i swapped it out rpms still drop and black smoke still there

Injectors, fuel pump, regulator? injectors been swapped out , fuel pump might be my culprit.

egr emissions? might delete it, would this cause my symptoms?

vacuum leak somewhere? but my problems occur only when engine is warm

battery power supply? i did ghetto rig the positive wire so its basically two pieces.

and my final guess would be bent/floating valve


help please.