Ok so i have owned a 89 civic for a few years now and have had nothing but constant issues. it used to run fine until my brother scrapped the engine running it hot until it died then it was given to me. i installed a junk yard d16a6 block with a sohc zc head. i have never (NOT) had idle issues with this car since all the swap. it was jumping around from about 800 rpm to 2000 and it turned out to be fuel pressure regulator being stuck after many dollars later. but now it drives like a dream and pulls hard for what it is but when warmed up it will eventually hunt from around 700 rpm to 1000 and then get to where it will just stall and die. it will usually start back up without having to give it gas and then run for another few seconds or min then die again. it has no check engine lights and fuel pressure stays at about 38 psi now. i have also rebuilt the engine thinking it was due to low compression, ALL CYLINDERS WERE ABOUT 90 PSI and now they are all at 150 which doesnt seem good but maybe my guage and the new rebuild has about 150 miles on it.
Parts that have been swapped are as follows
Tps and calibrated
ebay dizzy (didnt fix so bought used honda and same results)
Engine coolant temp sensor (honda)
Intake air temp sensor (honda)
Idle air control valve cleaned didnt work so bought an ebay one
new wiring harness
New skunk2 throttle body and skunk2 intake manifold
New plugs and wires
new Main fuse/relay
new under hood fuse box
Checked for vacuum leaks and found none. all ports are plugged, only two vacuum lines are for fuel pressure regulator and the line is new and the brake booseter and i disconnected it and plugged the port on im and made no difference.
i dont believe ive replaced o2 sensor but it doesn have code
new throttle cable and made sure it has slack
seems like if i back out idle screw all the way with the iacv unplugged it will run steadily at idle but when plugged in problems will start but with idle air control valve unplugged rpms will just bounce at about 3000 so i cant leave it unplugged
ive checked ignition timing the best i could with the idle trying to not hold very steady and its lined up with the middle three marks on the crank pulley.
im out of ideas and was thinking maybe it needs a tune with the upgraded headers, intake, throttle body, and zc cam even thought the cam is almost zero differnce. im also out of money and have already put about $1500 in this thing trying to get it right only because it was given to me for free.
when its cold it will start no problem and idle at about 1800 then start working its way down to about 1000 but about the time the fans come on it wants to start acting up. sorry for the rambling but im desperate and out of ideas and honest to god feel like ive read every article on idle issues i can find on google that pertain to 89-91 civics. if someone could point me in the right direction to get it fixed i would pay $10-$20 on paypal or something. Thanks everyone for taking the time to read this!

 

where do you live man what state? or country?
i can fix your car no problem but i have to be there
im in Nebraska

 

I'm in south Carolina. Do you have any thoughts on what to try?