318i acceleration/idle problem
 

ok, changed ignition control unit , problem now seems to be with acceleration. Bimmer starts fine idles at 850 rpm and is very steady at idle. Only a slight touch to the accelerator and rpm goes up then fluctutes and cycles aprrox. 800 rpm drop then back up to former rpm then back down again. after about 5 seconds of this, rpm reaches another stable rpm, example 2,200 rpm. upon slightly increasing rpm with accelerator depression the same cycling occurs. Thanks for any help.
Jan