Problem with my 05 6.0 work truck. After the truck is warmed up and i've been driven for awhile the dash gauge acts up. When i come a stop or light and at idle the check gauges light comes on and the oil pressure drops to zero. A slight touch of the throttle and the gauge shoots right back up but drops again when i come to idle. Truck runs fine when it happens so im assuming its the pressure sending unit. Any thoughts

 

As the truck doesn't die, it's your indicator or sending unit. Actual pressure MUST be good or it would die.

 

The gauge is a idiot light with a needle, sender it a switch @ 6 lbs.
I would check pressure with a gauge to be sure/

 

Thanks, i'll check the pressure for piece of mind, if its good i'll try the send first.

 

This issue has been brought up before by others. Check the black button in the bottom of your oil filter housing, if it is not being depressed by the filter or missing it will allow oil to flow out of the housing and straight to the pan, therefore not allowing the proper pressure to build up and trip the pressure switch. Enough oil may make it to your sump to feed the injectors and keep it running without building up the proper pressure. And because the LPOP is a mechanical pump driven by the engine it will flow more oil at higher RPM making the pressure switch read when you rev. This issue can be caused by using non Racor or non motorcraft filter and is why the guys on here harp on that.

Edit: the button I'm talking about is to the right of the standpipe in this pic.

 

Not saying it's not the sending unit, but the problem I stated above will cause the same problems you described.

 

I would also add pigtail to this list.........