Low Oil Pressure Under Heavy Braking

[Will Eastman 6]

I have posted this on my project thread but thought id chuck it here so as to get a good response as to be honest it is worrying me a little to say the least.

The problem is occuring with my recently converted mi16. It usually occurs with the car warmed up n running nicely on the motorway (has happened numerous times) and I pull off at a junction and slow rather heavily to a standstill, when slowing the STOP light on the dash starts to flash a little, then once sitting in neutral the oil pressure read very low and the warning lights on the dash come on. This can be remedied by a blip of the throttle, making the oil pressure rise. Any ideas what this could be?? I know the gauges arn't that accurate on these but surely this isn't ideal??

 

Thanks