Lexus IS Tank Ventilation Issue

The symptoms you describe do align with a potential tank ventilation issue. Have you checked the purge valve itself? A faulty valve can also mimic the behavior of clogged hoses, causing similar pressure imbalances within the fuel tank.

Good point about the purge valve. I was so focused on the hoses I didn't consider it. Is there a straightforward way to test the valve's functionality without specialized equipment? Like applying voltage to see if it clicks open, or am I oversimplifying things?

While a rudimentary voltage test might provide some indication, a definitive diagnosis often requires specialized tools to measure flow and pressure accurately. Given the potential impact on engine performance, I would recommend a visit to a qualified workshop for a thorough inspection.

Thanks for the confirmation and advice. I took it to a shop and you were spot on – the ventilation valve hoses were indeed clogged. They cleared the blockage, and the CEL is gone, and the stalling issue resolved. Total cost was 175€ Appreciate the guidance!