For the past 2 months my car has had the following symptoms: surging, 1500 to 2000 rpm hesitation, heavy engine braking when not on the gas ( it’s a manual) and just poor drivability. People on the internet including some big name companies say you have to repin this and swap manifolds to use a 2 wire iacv. This is FALSE. You can run a 3 wire obd2 iacv with an obd1 ecu. I am currently using a p28 obd1 ecu with an obd2 F20b and my drivability issues went away as soon as I connected this. The process is so painstakingly obvious I can’t believe I didn’t realize this before. I have actually facepalmed myself for not taking an analytical look at this before. So here goes. Basically you find whatever pin your ecu has for iacv and connect that to the black and blue wire on your 3 wire obd2 iacv pigtail. Then you connect the black and yellow wire on the pigtail to any other 12 volt black and yellow wire you can get your hands on. Then you just take the black wire on the pigtail and ground it. That’s it. That’s all there is to it. So to reiterate for anyone who cares Ecu/chassis side. Iacv pigtail side ————————- ——————— iacv pin —————> black and blue on pigtail Blk/ylw 12 v wire—> blk/ylw on iacv plug Ground wire———> blk wire on pigtail.