1993 300 SL 5 speed stick

I have a 1993 300 SL 5 speed stick with about 54,000 miles and drive it about 3500 miles a year. About two weeks ago I drove it after about 2 months in the garage. It was very hard to start and keep running. With the
idle about 700 rpm when the accelerator was pushed down the engine would stall. So I kept the rpm at 1500-2000 when stopped. The engine did not want to go over 4000 rpm. After about 10 miles it seemed to run normally and would go up to nearly 7000 rpm. I went to see my mother who lives about 35 miles away. Coming back it started and ran normally. The next day it started and ran normally. It then sat in the garage again for two weeks. Saturday it was difficult to start and would stall. I came back and turned around in my neighbor's driveway when it stalled across the street. I had to crank the engine for about 20 minutes before it would start. Sometimes it seems like it would fire on some cylinders but not all, other times not firing at all. Since the car runs fine after about 10 minutes/miles I thought it might be some kind of sensor or brain problems at initial startup. Someone else says some type of fuel delivery problems keep fuel from the engine and that is causing the starting problems. I would like to take the car to my mechanic on Friday or Monday with some idea of what might be causing the problem since by the time I get there [25 miles] it will probably be running nearly perfectly again.
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Fuel starvation.
If the fuel filter were blocked it would be so all the time so I'd discount that in favor of a fuel pump (or pumps) problem. The pump may be somewhat weak or worn after 15 years or just a bit gummy inside.
Before going to Mr. Mechanic I'd put two cans of Techron or equivalent fuel system / fuel injector cleaner into the fuel tank and give that a chance (a tank of driving) to work. Chances are good that the problem will be cured that way, if not, it's on to the fuel pump. But at least you'll first have ruled out simple gum or dirt in the pump.
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All good suggestions as I have no idea what could be causing such problem. In your case, there are some suggestions:
1. Use synthetic oil and change once a year or so.
2. Make sure your air filter is clean.
3. As TG suggested, run some fuel injector cleaner... Lubro Moly Jectron is good stuff. Lubro Moly Venti Sauber should be used together too. One for fuel injection and one for valve.
4. It is possible your fuel filte ris clogged... if you don't keep fuel tank full, chances of some condensation... but considering you do drive 3500 miles... that's about 12 tanks per year... which should not be an issue.
5. I would say you got some kind of fuel pressure leak... possibility of one fuel injector is bad or two. Taking out spark plug will reveal which may be the trouble one. The best test is done by mechanic with fuel pressure gauge and he physically pull out the injector to see which one is leaking.
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An additional thought: The EGR (exhaust gas recirculation) valve may be sticking. Others here may know more about the ERG than I and can opine on this idea.
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