My 1992 m50 e34 at times will not start. There does not seem to be a pattern to it. It will start fine... I go into a store and when I come out it will not start. There is power to the car (also new battery). Turn the key to start and nothing, it reminds me of when you try to start it if you leave it in gear. So now I wait... 5 to 10 min. and bam! it starts fine. Sometimes I don't have to wait, it will just start like it is supposed to on the first try. Could it be the starter relay? Please help.