fuel pressure light

["Partridge, David V." <PartrDV@domain.elided>]

Spica experts, HELP!
My 76 spider has started to wink at me with the fuel pressure light.
I replaced the main fuel filter last nite and thought I had solved
the problem but after 10 min. of running it began to blink again
under hard acceleration. I carefully drove home, switched off and then
switched it back on. The low pressure light now stayed on
unless I started the engine. Frustrated, I retired to the house
for a beer. After about 3 hours I went back out, switched the 
ignition on and the light blinked once and went out.
I assume the warm up and low pressure cycle would repeat
If I drive it again. What does this sound like?
Rear filter? (fairly new, PO claims replacement) 
Fuel pump? (PLEASE NO!) The pump runs and doesn't leak.
Or faulty pressure switch. 
Any help would be  greatly appreciated.
BTW: it runs perfectly at all times.
Dave Partridge
76 Spider
Monticello, Mn

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