I have a 90 300SEL that I only drive in the summer. When I brought it out of storage this spring it started right up and ran fine. When I jumped in to go for a spin and I stepped on the fuel it stalled and was very hard to start back up. It has been that way ever since. After getting it going it will not take fuel unless I feather the pedal. I have checked the breather and everything else for rodent nests and everything is clear. I assume it must be something electronic as it ran perfect when I put it away. What could change so quick over the winter? Anyone have any ideas what I can check? It is quite frustrating as I have no idea even where to start.