I had this problem on my 86 245DL. When you left the light it would stall, jump, surge, and then after a few seconds catch and take off. After it caught ran fine, only happened when you tried to take off.

It turned out to be the fuel pressure regulator was going out. Finally died a month or so later in a spectacular plume of white smoke and a dead engine running at highway speeds on the way home from work. The diaphragm had failed and allowed copious amounts of gas to pour into the intake manifold. The white smoke was unburned gas hitting the catalytic converter. She smelled like a gas soaked rag when I got out. It was a wonder it did not catch on fire.

So it might be worth checking out. Pull of the vacuum hose and if you smell gas change it out. If your timing checks out may be worth changing out also.

Regards,

Paul