Hey Guys

My 1992 735i has developed a odd fault. On starting from overnight cold it starts o.k then the idle drops and rises for about 5 to 10 seconds and tapers out to a contant idle. She drives a fine but idles a little unevenly ( only slightly) until hot and then perfect.

After 7 seven hours parked the same thing happens but much less and only for about 3 to 5 seconds.

I wanna get this sorted as I am worried something major is about to fail.

Thanks for any help