Michalson

Hi everyone, I am looking for some insight regarding a fueling issue on my Skoda Octavia 3 RS (2.0 TSI, EA888 Gen 3, CHHA engine, 169kW). The car is currently running an APR Stage 2 tune (ECU + TCU). The issue first appeared right after flashing APR Stage 1 at around 74k km, and now at 86k km, it has become more frequent (sometimes 3x a day, sometimes it gives peace for 2 weeks). The car drives absolutely fine, pulling hard from the bottom without any issues. It never enters limp mode, and there is NO Check Engine Light (CEL) or any warning on the dashboard. The only way I know there is a problem is by scanning the car and finding this intermittent fault code in VCDS: 15007 - Fuel Pressure Regulator Valve (N290) - P0089 00 - Implausible Signal Freeze frame data shows it always happens under heavy load: ~5050 RPM, 93.3% load, MAP at 255 kPa, HPFP actual pressure at 19,860 kPa (approx. 198 bar). What I found during data logging (LOG attached): At part throttle, the LPFP easily hits the APR-targeted 7.0 bar. Under WOT (Wide Open Throttle), the LPFP holds the requested 7.0 bar from 1300 RPM to 2400 RPM. The issue: From 2400 RPM up to 4700 RPM, the actual LPFP pressure starts dropping linearly until it hits roughly 4.6 – 4.7 bar, where it gets stuck and stays there all the way to the 6400 RPM redline. Meanwhile, the HPFP target and actual pressures follow each other quite well, actually climbing from 180 bar to 200 bar at 6400 RPM. However, the N290 duty cycle spikes like crazy because it tries to compensate for the missing pressure from the low-pressure side. Because the low-pressure side drops significantly below the requested 7.0 bar exactly when the fuel demand increases, I suspect the high-pressure pump (HPFP) and the N290 valve are actually fine and just reacting to a low-pressure starvation. Performance Logs I also logged airflow. APR Stage 2 Maximum airflow through throttle: 942 kg/h at 5495 rpm Knock retard looks very clean on all four cylinders. No significant timing corrections. The car pulls strong and does not feel fuel limited. My questions for the community: Has anyone experienced this exact linear drop to ~4.6 bar under load with APR software? Is this a textbook sign of the OEM LPFP control module (5Q0 906 093) overheating and pulling back back due to thermal protection, or is the actual in-tank pump simply tired and drawing too many Amps? Which revision of the control module should I get to fix this, or is a PM4 / aftermarket upgrade necessary for APR Stage 2? Any advice, link to a similar thread, or log analysis would be highly appreciated. Thanks in advance! Current setup: APR Stage 2 HJS 200 CPSI downpipe Milltek cat-back exhaust (non-resonated) Enlarged turbo inlet Upgraded turbo intake hose Intake restrictions removed/modified RacingLine ignition coils Fresh oil service New oil filter New air filter New cabin filter New spark plugs The car is still running the factory IS20 turbo.