318i runs rough after cold start

[karlh]

1994 318i 64,000miles. The car will run slightly rough and there is some hesitation for the first 3-4 minutes after starting the when the engine is cold. This is only with partial throttle. Runs fine immediately with 3/4 or full throttle. After this short warmup period, it runs perfectly. An independant BMW shop did a thorough checkout before recently purchasing the car. No problems or engine codes found. New spark plugs and air filter. Tried Chevron Techron fuel additive last fillup - no difference. Same thing regardless of grade of fuel. This only happens when the engine is completely cold ie. first thing in the morning. Is this a common characteristic of the 318i engine? Could be a warning sign of future problems? Any advise would be appreciated!

[turboman318]

i have a 97 318is. does the same thing when i haven't drivin it in a while and it's been in the cold. once it was about 10 degrees and the car had been sitting outside for a month, so the motor itself was probably 10 degrees. i started it and it was pretty violently idling, the exhaust was shakin all over the place, and wheni'd give it gas i'd see black smoke coming from teh exhaust. thats normal to expect with any car when you start it cold.