0 Oil pressure after highway driving? Bad oil pressure sending unit?

[Suprajay]

Ok so I have a small problem. I just rebuilt my 7mgte and have done some mods to it. I'll list them after I describe the problem. Well the problem I'm having is I put in an aftermarket electronic oil pressure gauge from glowshift. Driving around town or on the highway my oil pressure stays around 30psi no fluctuations (new oil pump shimmed 5mm with the -AN upgrade). My problem appears after driving on the highway for a little while and getting off my oil pressure drops to 0 psi sitting at stop lights or stop signs. I stopped and pulled my oil cap off and looked in and I still have oil flinging around on my cams and no chattering or strange noises of any sort. The car runs beautifully. Now when I looked at the gauge it said it only reads 10-145psi. During normal driving just around town and stopping at stop lights/signs I have around 8-10psi. (of course this is all around operating temps.) Now could it be that the sending unit isn't calibrated to go below 10psi and that's why my gauge is giving me 0psi? Another thing I've thought of is that the sending unit is kind of close to the exhaust manifold. So could it be getting to hot? I have it in the spot where my old sending unit used to be. But it is much taller then the factory sending unit. Any help would be greatly appreciated.

List of Mods:
New oil pump shimmed 5mm
driftmotion -AN line going from oil pump to block
driftmotion -AN soft line kit for the turbo
3" BIC ddp
driftmotion intercooler kit
driftmotion egr block off kit
clevite 77 main and rod bearings
57 trim ct26

Again any help would be greatly appreciated. Thinking it might be time to hook up the old sending unit and use the crappy factory gauge again.