Was trying to buy a k20a3 In a 2000 civic and during test drive in 5th gear at about 60mph downshifted into 4th and the engine didn’t respond at all, then after a few seconds started to accelerate like normal. Looked at the setup and it had stock fuel rail and didn’t see a fuel pressure regulator. Also check engine light was on but when I tried to scan for a code it only said emissions.