jdm b20b swap with 47000 kilometers with ls intake manifold

idle was adjusted by service manual and timing set
new plugs and cap/rotor and coil new fuel pump


car is idling fine then randomly( at least it seems like) idle hangs at around 1500 rpm

driving or sometimes after I rev it up in idle

it will do it for few minutes then drop back to normal suddenly

and also car skips a beat once in a while during idle I don't know if its a misfire or problem with ecu losing connection or whatever.

im using Neptune and idle is set to 14.5-14.9afr in 600-1500 range I spent some time getting it nice and consistent but it still hangs and skips

im using same iacv that I had on last engine that worked fine
changed map sensor and iat just because I had extras...

 

are your coolant bypass hoses hooked up?

 

Yep

It just does it randomly when im driving or idling

 

Just noticed that it also bounces slowly
Not very fast like when the iacv is bad

 

remove your intake air tube when your car is having idle problems and look down the throat of the throttle body. If you have a manual transmission throttle body there will be a port to the left of the butterfly that feeds the IACV fresh air, block it with your finger and if your idle steadies out then your IACV is to blame. If you have an automatic throttle body there will be two ports to the left of the butterfly, the upper one feeds the IACV and the lower one feeds the FITV. Block each one at a time and you'll find out which is causing your idle problems.

edit: you should also check your vacuum hoses for cracks/leaks

 

its just kinda random

I will be at a light and it will hang for few seconds then drop to normal.
or I will be warming up the car and idle is dropping slowly as it warms up
I give it gas and it hangs for some time then drops

a lot of times it doesn't do it.
the engine is jdm b20b with 29k miles from a 2001 crv with ls intake and obd2 alternator and engine harness. as far as I can tell its plug and play into obd1 car

I cleaned the throttle body before I put the engine in(took it off and cleaned everywhere)
cleaned iacv its spotless inside
cleaned the idle adjusting screw
theres no FITV
throttle plate closes and tps is calibrated in Neptune
iat sensor is good
but im not sure what to do with the solenoid on top of the intake manifold im guessing its the purge solenoid for obd2 its plugged in and hose connected to the evap canister with a hose that goes to throttle body on obd1 car
its in open loop with a wideband and tuned to 14.5-14.9 idle from 700 to 1500 rpm

 

bump?
it keeps doing it randomly at same rpm between 2500-3000

today it did it more
drove it in the morning and daytime no problem
took it through gears full throttle 4 gears not a hiccup.

go get coffee and idle for few minutes then drive off and it starts sputtering with maybe 50-80% throttle.
did it 3 times in a row.
the maps are setup for 14.5-15.0 with no lean or rich spots.
I have no fn clue why it is happening as the engine only has 29000 miles and has no problem during hard acceleration

 

any help would be preciated its hard to drive and pretty unsafe when its choking right when I need to accelerate and its doing it randomly that I cant trace the issue.

afr gauge shows all kinds of fucked up when this happends.

and I don't think theres issue with fuel pump/filter/injectors because I can pull through 4 gears at WOT with normal fuel numbers

and then will drive across the city and this **** starts choking after every stop light

 

bump

 

I cleaned everything already

is 89mm crank more sensitive to lean mixture and detonation than 87mm?

I think the problem with the tune where its shifting the fuel values like it did always.

only this engine is more sensitive when it gets leaner it starts hesitating

I noticed ( at least for now) that it went away when I increased the fuel multiplier value.

 

upload the map i sent you and see if it still happens. if so there is some kind of mechanical issue. if not, your problem lies in the tune

 

I was able to get better fuel tables with ls maps i tried yours and it didnt run that great