Problems shifting into first (hesitation + odd idle) please help

[DarCwuN]

Hi all,
I am having this problem with shifting into first and reverse. I recently got this 95 318i 80k 5 speed. I am not used to this cars cutch but I think this may be a problem. When I got the car it was impossible to drive from a stop because every time I let go of the clutch the car would die, I would have to press on the gas and could only let go of the clutch when the engine was at about 2300rpm. I checked under the hood and found that the throttle cable was loose so I tightened it up a bit which made a huge difference but even now I have to at least have the engine at about 1700rpm before letting go of the clutch if I don’t do this the car hesitates and may or may not die. I can not tighten the throttle cable anymore without raising the idle. Once successfully in first the car drives normal. The other thing I noticed is that the idle is erratic the car seems to idle around 750rpm but when you let go of the gas it falls to 1000 stays there for a sec then goes to 900, stay there a sec then drops to 750rpm where it stays but every now and then I will see it jump up and down from 750 to 900 on its own but this is rare. What do you guys think is this a problem or not and what may be causing it. Can it be any one of the following, vacuum leak, bad fuel filter or pump, throttle cable problems, dirty throttle , bad o2 sensor, old spark plugs, old fuel injectors. I have been driving manual cars for 10 years and have never come across a problem like this. Any help would be appreciated.
Thanks

[Jared at Pelican Parts]

First off,

I would check all the vacuum hoses/connections. This is most likely what is causing the problem. Also check the valve cover gasket as well as the idle control valve and the throttle switch. When the idle control valves go out, they cause a fluctuating idle problem. Most times, you simply need to clean out the valve, as then can get gummed up and start to stick. The throttle switch is located at the bottom of the throttle body and is used to indicate if the engine is at idle or full-throttle. If it is out of adjustment it can cause this problem. Vacuum leaks can also cause the lack of power you are describing.

[DarCwuN]

Thanks Jared for the great info. The car is going to the tech shop tomorrow, I will print out your reply and give it to the technician. I was wondering if you can tell me if belts installed improperly could cause a similar problem, because before I bought the car it drove fine then the tech replaced squeaky belts and sold the car to me, at this point I noticed the change. Let me know.
Thanks again

[Jared at Pelican Parts]

I dont think this would have anything to do with the belts. You might also want to clean the injectors and change the fuel filter.