I am technically inclined so shallow and obvious suggestions have already been done unless i am completely overlooking something. This is on a 2000 integra gs-r, b18c1, 156k miles. Only modifications are IAT relocation to intake tube, issue is actually worse with IAT in port on stock gsr intake manifold. It has full 2.25inch exhaust header, test pipe, and catback, and short ram intake with K&N filter. Issue is as stated and identified via scan tool through stock denso narrowband, car will throw a P0171 and generic fuel trim code intermittently during hot starts but no other codes have shown up. Car doesn't have a audible miss at idle or during acceleration and fuel trims are normal above 3k rpm. It also seems to being running mean lean and if not for the random code and watching the scan tool I probably wouldnt even bother messing with it. I can watch long term gradually rise to around 17% at idle but during highway cruising it will gradually reduce to around 6% lean. Mechanically engine is good, compression test showed 238-243 psi between cylinders and done with throttle plate wide open. Leakdown test at worst showed 6% and at best 4% between cylinders. Engine has had intake and exhaust valves replaced around 8k miles ago but issue started within the last 3 weeks, no repairs were performed coinciding with issue. No vacuum leaks present at the moment, I have checked with propane and brake clean. I even plugged every vacuum hose and ran a single hose to FPR which did not change or vary the issue. Manifold vacuum is on spec from service manual around 22 inHG. I have checked resistance on all wires for AFR controlling sensors such as primary o2, IAT, MAP, TPS, and ECT. Fuel pressure is perfect 43 with vacuum and 52 without. I have replaced the upstream o2, ECT, and TPS sensors with little to no change. The dizzy is less than 5k miles old and every other sensor on the car has been replaced within the last 10k miles. I have tried 3 sets of fuel injectors which have helped but by no more than 2-3%. The only other problem with the car is it burns oil. It doesnt burn a consistent amount either, sometimes its a half quart a week and other times its a half quart every 2-3 weeks. I drive roughly 250 miles a week which seems like the oil burning is extremely excessive considering compression and leak down numbers. Considering what b18c1's are going for on Ebay I am tempted to sell the engine and trans and just K swap it since this car has had nothing but problems the whole time I have owned it. Any input that isn't the generic hondatech go to like "check fuel pressure" or "clean your IACV" is greatly appreciated

Also forgot to add that I have 2 obd2b p72's programmed for the car and a obd1 p72 that do not change the issue

 

You figure this out?

Stock motor and ECU?

 

Nope, I have tested all wiring, replaced full exhaust system and made sure its all properly sealed. The oil burning was a stuck open pcv valve. Now it burns under a quart every 1000 miles. Still it gets stupid lean at idle and its starting to act up at all rpm's. Its manifested into minor hesitation until up to operating temp. I have tried 3 different ecu's, changed to a coil on plug setup (digidizzy), and replaced the o2 sensor. This past week I stepped up from a stock fuel pump to a 255 which made some of the hesitation i was experiencing go away. Still it runs crazy lean according to short term fuel trims and long terms get up to 15%-18%. I can find absolutely no issues whatsoever and I can tell its not running lean. Even before the 255 full pump its running hella rich because I can smell it. For whatever reason the ecu thinks its running lean and fattening the afr's. My next step is to tune it out with hondata once I get the money together. Are you experiencing something similar?