sr20det skyline idles like crab but drives perfect

ok so i have an sr20det in my skyline the engine has bin fully rebuilt top to bottom the timing is perfect including the cas alignment also the vacume gauge always reads 17-20 untell the rpm drops below normal level the veicle has no cat the 02 is brand new the maf is new knock sensor is new ecu and also the spark plugs are new the coil packs have all bin tested fine has a new 300zx ignitor also i have tested all fuel injectors for continuity and just for shitts a ground wiring kit also code 55 is present at this point i am compleatly stumped and have no idea weir to look next so the car idles ruff missfires randomely at idle only and shakes a lot! any help is greatly appreciated oh and i almost forgot the wiring harness is also new from wiring specialties

mod list
hks giant fmic
hks ssqv
hks piping
cx racing aluminum rad 12inch fan
apexi air filter kit
silicone vacume hoses

apexi air filter kit

idle air control valve maybe?

We flushed the IACV when I built the motor and it was perfect when we pulled the motor from my car but you never know… You have a spare sittin around by any chance ciaran?

throttle position sensor might not be set properly at idle, especially if this is rebuilt, as at some point you would have touched it.

`Mod edit title please… lawl.

also is there a way of testing the iacv. I have pulled of the hose that conects to the intercooler pipe while its cold if i plug the piping side it runs the same but wence the car is warm when the hose is pulled off the car stalls and i can feel the airflow going thru the hose unlike when car was cold would this not indacate a good iac beacuse it opens and closes according to coolant temp

also the i do not believe the tps was moved during the swap mabe it was but i have marked it were it was and truyed it in every other position does not seem to make much diffrence during idle at all but the tps is back to its original position now beacuse the car seems to run the best that way

billy i have a spare one you can have, its the one that came off your old sr

ok so we changed the iac with a cleen new one no diffrence still stuck and dont no were to go from here any help is appriciated and thankyou very much ciaran for the iac let me no if u ever need any car help bro.

tps position

TPS position as mentioned or possibly the Coolant temp sensor for the ecu.

Or the IACV isn’t wired correctly… it should click as it pulses air into the chamber.