Oil pressure problem
Oil pressure fine at operating temp,
when cold good at idle. throw a couple
revs at it, drops to zero. back off the
throttle for a couple seconds, back to
normal. I haven't seen any description
quite like that. '05 avalanche LT 5.3
bought her 2 years ago with just a tick
over 100 large on the clock. switched
to full synthetic at first oil change. now
approaching 140. saw a lot of good
advice here, but nothing this specific