Is it possible that your engine oil is getting too hot? Perhaps the oil cooler malfunctioned after being disturbed.
Oil pressure tends to drop as the oil heats up.

Sent from my iPhone

> On Feb 28, 2015, at 11:44 AM, John Rodgers <jrodgers113@GMAIL.COM> wrote:
> 
> Oil is Kendall GT-1 20W50.
> 
> At idle, flickering light, turn the engine off, then restart, the light no
> longer flickers. It might, or it might not, flicker at the next stop.
> 
> I have never had a low oil pressure indication before. But the engine was
> out of service while the oil cooler seal was replaced and two pushrod tubes
> were replaced on the side opposite the oil pressure switch. That switch was
> undisturbed. When the van was again put on the road, the first time out,
> the light flickered at a stop. Am mystified why it has never flickered
> before, now suddenly it does. Engine has 114, 000 odd miles on it.
> 
> John
>> On Feb 28, 2015 12:58 PM, "Dan N" <dn92610@gmail.com> wrote:
>> 
>> either the oil pressure sensor are bad or you have a low oil pressure ..
>> 
>> what grade of oil are you using?
>> 
>> On Sat, Feb 28, 2015 at 10:45 AM, John Rodgers <jrodgers113@gmail.com>
>> wrote:
>> 
>>> The oil pressure light comes on after a long run at speed when I have to
>>> drop to idle and stop for traffic or a stop light. Doesn't happen every
>>> time but frequently enough to keep me spooked. I have checked the wires
>>> and
>>> found no faults. What is happening. What else might cause this?
>>> 
>>> John
>> 
>>