I just got my dc5 today. It seems to hesitate with half throttle around 3700 rpm and then goes fine. At full throttle it goes nicely. The clutch catches high to me, it has 90k miles and I had Honda check it before I bought it and they said it was fine. I haven't had a Honda in a while, anyone else's clutch catch high. It seems to catch fine. The guy I bought it from said he did not have his issue but that it may be a dirty O2 sensor. He also said his buddy said in Japan these cars are tuned to 95 octane and that could have caused the O2 sensor tonbe dirty. There is no CEL. My other buddy said it could be IACV. What do you guys think?

 

Sounds to me like the guy that sold you the car would tell you anything to sell it, and new there were issues but never felt like addressing them. Honda will tell you it's ok because they are a dealership and all they do is replace parts, diagnostics is done with a scanner or repair manual there. Clutch catching high if it's a stock clutch is the clutch itself (telling you replace me). Type R is factory tuned on 93 octane, so that theory is dead, iacv only effects the air coming in at idle and has nothing to do with rpm at 3700k. I would do a compression test, valve adjustment and inspect the cams for irregular wear. "Dirty" o2 sensor would throw a cel for o2 fault, the seller seems like a real stand up guy 😒

 

Ditto the above^^^ the normal diagnostic checks need to be done, compression test, valve lash adjustment, check the fuel pressure, check the spark, use only an HEI spark tester, [around $10 at any auto parts store] spark needs to be bright blue.
Check timing confirm both mechanical and electrical timing. 94