So, I want to first apologize because I know there are plenty of these threads here (I have searched almost every one). I have used a lot fin my quest to get the car running right. I am a relatively new owner of an 05 S2000 that I picked up for a steal. It of course has a couple minor issues given the price. The guy I bought it from had already replaced the plugs with new NGK Laser and the Airfilter with a K&N. He assumed the condition was because of the Secondary Air Pump (which I replaced with an Izze Racing delete kit). I only know of it operating in the current state, so I cannot gauge how normal is supposed to feel. However, there are a couple of issues that are intermingled somehow that I am trying to chase down.
First off the symptoms:
1. High idle at start and after warm up. Began at 1300 and now (a couple of weeks and attempted fixes later) now is at 2000.
2. Resetting the ECU does temporarily lower the idle to a sensible 800-900 however this feels lumpy and as though it is misfiring
3. Low idle/ stall with the A/C on (goes away if moving at a normal speed). Allowing to almost stall does temporarily raise it to the 1300 I have bee experiencing.
4. Rich gas smell when idling
5. Hesitation when turning off.
6. P0172 - Rich Bank 1

Things I have already done (thanks to the threads out there)
1. Attempted to allow it to correct itself
2. Whacked MAP (reset ECU by fuse) then replaced MAP (reset ECU by battery)
3. Cleaned IACV (reset ECU by fuse) then replaced IACV (reset ECU by battery)

So, now I am trying to work my way down the list from least costly in efforts to get this thing corrected. This is where I could use any assistance or advice in getting thise issue resolved.
1. I will be removing the TB and cleaning it, but do have a 70mm Ballade unit that I am contemplating swapping for in advance of the work I plan to do.
2. Check voltage on the TBS which I need to thoroughly read. I found one for a Civic EK, so I don't know if the voltages are the same for an S2000.
3. Adjust valves. I have the kit coming in because it is something that I will have to do regardless.
4. Swap the upstream O2 sensor for a new one. Is there a way to tell which one it is based on the code?. I plan on doing this with the H/T/E I have purchased.
5. Swap out to new ignition coils.
6. Swap the motor mounts.

This is all I have been able to find in my searching. Is there anything that I could be missing here that could be causing the issues? Any assistance in helping to correct this would be greatly appreciated. Thanks!

 

Doesn't P0172 - Rich Bank 1, mean faulty front O2 sensor? Maybe, replace it with a new one. Instead of swapping front to back?

 

I meant swapping to a new one. Sorry for that confusion. Fixed.

 

So, I pulled the throttle body, and it appears to be clean. I started to swap everything over to the new Ballade unit, but have hit a couple of snags. Does anyone know the bolt size for the MAP? Mine have stripped at the head, and I think I have one more Dremel cut left for making a flat tip slot. Also, by chance, does anyone know what the bolt size is for the TPS on the Ballade unit? Lastly, I searched for TPS with no luck (minus an Omni unit) so are there one's compatible with our set ups or the Ballade unit? I have went ahead and ordered a new O2 sensor in effort to move this thing down the line. I am also contemplating a Ballade IM to flow more air. I know its a debated item, but its pretty inexpensive and might as well have if I decided to go supercharged.

 

Anyone have any of good input or experienced anything similar? I am going to pull the plugs and possibly check compression, but after that I don't really know where else to go. I am hoping that the O2 sensor will fix the issue.

Separate note...Anyone have experience with the ballade IM and TB setup on an N/A setup? I plan on doing an S/C at some point, but thought I might as well do some ground work. I am guessing with a CAI, larger TB and IM, H/T/E, and tune (AEM v2) I could possibly get maybe 210ish whp at sea level depending on the dyno with a lot more punch mid range. Maybe lower the VTEC engagement to 5100 RPM?