I have a bmw 318 ti 95 my problem is it keeps

you may want to check the engine's timing. You may want to check also the spark plugs as it may tell you if you are advanced or not. A black tip spark plug would tell you that the timing is late while a little white is advanced. You need is a light brown color. If there is no problem on the timing you may want to check on the fast idle control valve and pcv if it needs a little cleaning.