I recently installed new heads / cam. Yesterday while driving to work, towards the end of the trip, my oil pressure was about 15 psi lower than usual at idle, but it cam back up to pressure above idle. My first thought was a sticking pressure relief valve (fairly new ls6 pump, ported and shimmed). Its possible that I still have some chunks of my old broken lifter rollers floating around in the oil, or even some aluminum filings from flycutting. A quick rev dislodged whatever it was and my idle pressure cam back up. I was running fresh dino oil only a day old. I changed that oil when i got home and put new dino oil in again, which i plan on changing for my usual synthetic this weekend. Since then Ive seen the gauge fluctuate just a hair, maybe 5 psi difference at idle throughout the course of the morning commute. Do you think this is really happening to the oil? Maybe i damaged the sending unit putting the intake back on? Or perhaps I have a loose ground or something. The night I first fired it up (sunday night), for a split second all my gauges went down to zero and then came back up immediately. The motor didnt hiccup at all. I figured it may have been due to the extreme cold it was sitting in for so long. Hasn't happened since. Any ideas what I should try first? I dont have time to poke around until saturday, so i figured id do some homework while i wait for the weekend.

 

With all the gauges going to zero for a second sounds like a elect problem there, like you say loose connection or ground.
As for erratic oil pressure indication-low I would look close at the OP sender and it,s connections. If you think you have contamination or had, might try and pull the OP sender out and do a good flush and clean. Might have something blocking the inlet.

 

As for the ground on the back of the heads, theres three rings on the drivers side, and only the one bracket on the pass side head, right? Anything else? I know I also had some foam in my oil from condensation after sitting so long (3 weeks in the cold with an open motor covered in plastic). Could water have contaminated the sensor? Maybe a few drops of coolant spilled into the oil when i removed the heads? I think if i broke the sensor while removing or reinstalling the intake, it would either work or not work.

 

Different motor, but I did an intake on my Pontiac 3.1 V6 and am having similar issues. I think its electrical though.

The only way a "chuck" could stem the flow of oil is if it was stuck on the pickup, and reving it wouldn't dislodge it but would likely adhere it harder. I think your issue is electrical.

 

A chunk or small filings could jam the oil pump pressure releif valve pretty easily. If it were open ever so slightly, oil could bypass the system at idle. Even at its absolute worst, my idle oil pressure never dropped below 30 PSI. Its usually about 45 PSI fully warm at idle.