I have an irritating knocking sound that happens sometimes, as i start pulling away. It starts of slow they speeds up until i can't hear it anymore. When i slow down the knocking starts again and when i'm about to stop i can hear a slow grinding as if metal to metal. This started last week on a trip away and is now becoming more frequent.
I have recently had the buzzer of doom go off when driving between 30 and 40 mph, but took it to the garage for a oil pressure test and they said all was fine. Do you think the knocking and 'buzzer of doom' could be linked.
Does anyone have any ideas as to what could be the culprit of the knocking sound? i've had a look under the van and there is nothing obvious.
The van is a 1.9 petrol automatic.
It doesn't sound good, I dearly hope its not gonna die on me

Thanks in advance