Flashing CEL and Rough Idle on VW T-Roc, Urgent Help

Had similar symptoms on a 2017 VW Golf with the 1.4 TSI engine. The check engine light started flashing, indicating a severe engine misfire that needed immediate attention. The rough idle and stalling matches what you describe, and initially it seemed like a fuel pressure regulator issue. After proper diagnosis, it turned out the fuel filter replacement disturbed the fuel delivery system, allowing contaminated fuel to reach the injectors. This created an uneven fuel spray pattern, causing multiple cylinder misfires. The fix required: Cleaning all fuel injectors, Installing new spark plugs, Resetting the fuel trim values, Replacing the damaged fuel pressure regulator The severity of the issue meant continuing to drive risked serious engine damage. The symptoms worsened quickly from initial onset, especially during acceleration. The engine misfire also led to increased fuel consumption and poor fuel efficiency. For proper diagnosis, the mechanic needs specialized diagnostic equipment to read fuel pressure values and monitor live engine data. This helps distinguish between a simple fuel delivery problem and more severe engine issues. These symptoms should not be ignored as they can lead to catalytic converter damage if left unchecked.

Thanks for the detailed explanation about the fuel system issues. Really helpful how you broke down the diagnosis and repair process. The symptoms you described match exactly what I experienced with my T-Roc. The engine misfire was quite scary when it first happened. Just curious, do you remember roughly how much the total repair cost? My fuel pressure sensor also started acting up a month after the initial fix, wondering if you had any similar follow-up issues? The fuel pump seems fine now but always good to know what to watch out for.

After getting everything sorted with the fuel system and engine misfire issues on my Golf, the repairs worked out well. The fuel pressure regulator replacement fixed the problem completely, no more rough running or check engine light warnings. The defective regulator was definitely causing those similar symptoms you experienced. Got the error codes cleared after the new fuel filter installation, which cost 45€. The complete repair, including parts and labor for the regulator replacement, fuel injector cleaning, and diagnostic work totaled around 650€. No follow-up problems with the fuel pressure sensor or any other components since the fix. The engine runs smoothly now with normal fuel delivery and no misfires. Just make sure your mechanic properly bleeds the fuel system after any fuel-related repairs to prevent air pockets causing rough running. If your sensor is acting up, get it checked soon since incorrect fuel pressure readings can damage other fuel system components over time. Regular fuel filter changes also help prevent these issues from recurring.

Thanks for the input. I finally took the car to a different mechanic who really knew his stuff. The symptoms matched perfectly with what was described here. The mechanic ran a full diagnostic check and confirmed the fuel pressure regulator was failing, causing unstable fuel delivery. They also found contamination in the fuel rail that was affecting the injector spray patterns. The total repair came to 780€ including: New fuel pressure regulator, Fuel system cleaning, Injector service, New fuel filter, Labor costs Been driving for 2 weeks now and the engine runs perfectly, no more misfires, stalling or power loss. Fuel efficiency has improved noticeably too. Really glad I got it sorted before any serious engine damage occurred. My advice to others: dont wait if you notice similar symptoms. A proper diagnosis by a qualified mechanic is worth every cent compared to risking major engine problems.