Way back in the good old days we used to dis-assemble them and drive a certain pin back out a little. It's been so long since I"ve done it though, I can't describe it from memory. If I saw one I'm sure I'd remember. Anyway, after re-assembling and re-installing it I would connect a fuel pressure guage and let it sit overnight. IMMEDIATELY following cold-start, I would tap that pin (previously driven out ) back in a bit until the fuel pressure was back in spec. This cured a severe hesitation on acceleration when cold. If I remember correctly, this procedure is not found in any repair manual or MB service literature. It was just an inexpensive alternative to replacing the regulator. I hope this helps