Chevrolet Repair: 1999 chev sub 4x4 fuel pressure, fuel pressure, well pump

Question
installed new fuel pump, after old one quit, new one worked for a few hours then also developed low fuel pressure, replaced with new pump and after 5 hours of high speed travel it also developed low fuel pressure (would not accelerate)I am now thinking its malfunction rollover switch . any recomendations?

Answer
Did you replace the filter with the new second pump?  Sometimes when a pump comes apart the copper or brushes will disintegrate.  Make sure you don't have a bad pressure regulator as well.  Pump can be checked thoroughly with a low amp probe and an occiliscope.

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