Revs???

[lessteaks]

Hi all,

Just curious about why this is happening with my '84 500SEC.

First car drives very well etc. but every now and again revs drop from approx. 770 to about 450 and the oil needle drops to 2/3s and flickers slightly for a few seconds. Car remains very smooth etc.. When revs are at 770 revs the oil needle is at 3/3 etc.??

Only happens every now and again? Any ideas?

Thanks.

Les