Ill give car info first,
1995 honda DelSol VTEC
1996 ITR motor swap from (HMonline) 3 years racing without fault.
Matching P73 OBD2 ECU, Came with motor. Its not a short body ECU but it came with the motor so not sure if its JDM or not. We also ordered the Rywire ECU jumper and injector jumpers when we bought it. Already had the MSD distributor jumper. Worked great for 3 years.
D/B series aeromotive adjustable fuel pressure regulator.

Quick and short, I have a mis-fire at idle, and light throttle at the first of the raceday. The longer it sits around idling to warm up the worse it is. after the warm up lap it normally goes away, or a lap latter. Air/fuel reading is 11.8-12.4. (Thats where it normally is) Once the race is going it works as it always has. Great. Start up for the next race and runs great. Pre-season prep I put a new igniter and coil in the distributor, but ordered SIR not knowing it was different then ITR stuff. Took 4 distributors to build 2. 1 OBD2A and 1 OBD1. I put the OBD2A in the car as its the newest. New fuel filter in the car as well. Worked great around the yard before i switched everything, but never had it warm, and all pre season prep. At the track we looked at Fuel pressure, witch was good, mid 40s or so, Plugs look good. Intake is clean, no CEL, and Timing belt is set right. Cant see any damaged wires, but they dont really make scene as its only at idle/warm-up. WOT warm works great.

Right now my plan is to pull the injectors and clean the little filters in them, along with clean out the rail and the adjustable fuel pressure regulator. I have some OBD1 B17 injectors i can swap in from our old setup as well.

Long story with more details
So i drove it into the shop back in may, ran great. Pulled the distributor off as i had a new honda igniter and coil for it. Did not know the SIR and ITR distributors were different. (all parts ordered were for SIR B16B) So I tore apart 4 different distributors and built 2. Both having new igniters and coils in them. At the same time i put a new Honda fuel Filter in the car. Started the car up and it had a miss. Very light and went away quickly. Figured it was either bit of air in the fuel system or just the new parts coming alive in the distributor. Reved up great. Set the timing 16 degrees with the jumper in, and off to the track we were. Started at the track and it had a miss again. gave it a once over, fuel presure was good, Air/fuel ready was 14.7 or so at idle. Gave it a few revs and it went away, but still had a odd sound to it. So we took off the new plug wires and tossed on the old one. No change. Hit the track and it still had a little miss. 1 lap in and it was all good. Figured it just loaded up with fuel or something. Worked great until 3rd race when it developed a miss in high revs. Keep working its way down as the race went on. From 9000RPM to 7000RPM. lost a position due to it lol. Anyway switch to the other distributor i built. its a OBD1. Went back out and all was good.

Seemed okay preping for the next race, but still would miss at random.
Opened up the OBD2a distributor that acted up on me and found the wire from the coil to igniter was burnt and very loose at the igniter. Fixed the end and put it in the trailer as a spare.

Get to the track in June..... misfire. constant miss at idle, but everything looked fine. Put my hand near the header pipes but could not feel a difference. Hit the track, took 2-3 laps to clear up, worked great the rest of the day.

Checked over again, plugs look good, Air/fuel normal. Everything seems right but cold start, idle it mises.
Only other thing it has done lately is starting problems. Has good starter, power to the starter but wouldn't even kick in. Nothing. It has battery power to starter motor, but when starting it only has 10.5 Volts at the solenoid. Check over system but could not find a problem. Ignition switch failed years ago so it has a basic push button setup with ignition switch. Put it all back together and it started fine. Started fine once hot as well, but at random would kick out as soon as it engaged. Jumped it fine. So i deleted the starter system before June, wire from the kill switch to the Push button to the starter solenoid. works as it should.

Anyway, as luck would have it, this is basically the first time any of my hondas have acted up. 95 civic CX for Autoslalom, and a new build 99 Si for roadracing. All seem so happy. But this delsol can be the devil. But its been a suspension nightmare. Motors been so nice to us...
Any help/ideas are appreciated. would love to have it sorted for July 30 race. either way its hitting the track. lol.