Mercedes SL engine stalling issue resolved

Stalling at idle and a check engine light definitely point to a ventilation issue, possibly what you said. A clogged hose on the tank ventilation could trigger that. Is your pressure sensor ok? That's on the same circuit. Maybe that's faulty? If it's just hoses, that's not the end of the world. But I'd still check that sensor before you start ripping things apart. Could save you some time, and some cash maybe.

Thanks for the quick reply! Good point about the pressure sensor, I hadn't considered that. I'm not really sure how to check it though, is there a straightforward way to test its functionality or do I need special equipment?

Well, without proper tools, it is difficult to exclude a problem with the pressure sensor. It might be best to just take it to a workshop. They'll have the gear to diagnose it properly. It's probably a clogged hose like you originally thought, but it's better to be sure, right? Saves you throwing parts at it that you don't need.

Okay, you're probably right. I took it to a local shop, and they confirmed it was the tank ventilation valve. Turns out one of the hoses was, in fact, clogged. They cleared it out and replaced a cracked section of hose, and now it's running perfectly. Cost me about 175€ all in, which seems reasonable. Thanks for the advice!