Truck Repair: oil light, oil pressure switch, oil gauge

Question
Hey van,
Just wondering if this would mean anything when the pressure drops it's only at idle when im on the gas it rises then stoped at a light the presure drops to where the light will come on. Does that give you any idea on anything els it could be thanks.
Jeff
Followup To
Question -
Hey Van,

You just informed me about my oil pressure but i got one more thing to ask,  when i start my truck oil pressure it 225 on the oil gauge but eventualy it drops to the point where the oil light goes on? like i said the engine only has 50 000 kms on it, could it be the pump?
Answer -
Hi Jeff,
The pump could have some wear where the pressure could be a little low, but it would surprise me if it ever got that high.
The oil pressure switch could be bad, or the oil could be diluted with gasoline, especially if there has been a miss for a period of time.
If you decide to replace the pump, that would be a good time to measure the clearance in the bearings with Plastigauge.
Van

Answer
Hi Jeff,
I assume your idle speed is up to spec.
That would mean the oil is escaping from the confined clearances faster than it is being pumped.
Either the clearances are larger than before, the pump is worn, or the oil is breaking down.
Or a little of each.
You could try a heavier oil, or some STP additive.

Check this link. I call it more than you ever wanted to know about oil.

www.viperclub.org/articles/oilfaq.html

Van