1998 Other Saturn Models turns over but occasional hard star

I have a 98 saturn SC2.
Sometimes, when I attempt start, it cranks and starts, then the engine immeadietly tries to stall. I can get it to stay on, by holding down the gas until it works itself out.

While on the gas, it sounds like it catches then tries to stall over and over again, sometimes causing wrather violent vibration. I usually need to keep on the gas(between half to floored) for about 10-30 seconds, all the while smelly dark smoke is comming out of the exhaust.

It does not always happen, but I rightly expect it to happen under certin conditions. It always seems to happen when it is raining out, or if I give the car a bath(wash it) and I can reproduce it in fair weather, by turning on the engine for 1 second, off and restart immeadiatly. Sometimes it takes a try or two to make it happen, but it has never failed. In good weather conditions, and normal driving it usually seems to be fine.

The check engine light does not come on while driving

The car does not use much oil(anywhere from 1/2 to 1 quart between changes) but the exhaust always seems to smell a bit.

I resciently changed oil(i do every 3k), and with it I did the plugs, wires, and air filter(they where due)

The problem presist.

Any thoughts?