issue with aftermarket oil pressure gauge

1998 Dodge Neon

ok I am asking cause I think I might be over looking something...

I mean the AEM gauge really kills its reading, wonder why that is

the oil and vacuum/boost gauges are made by Megan Racing

ok... I rewired all my gauges using a nice terminal block...

tested voltage at the battery and at the barrier it was 12.31v car off (had doors open and radio on for few hours)

used a relay... the blue ignition wire turns on the relay which recieves power from the constant 12v red with ?white? tracer under the dash

its grounded to the single screw on the head lamp switch

the wire on the sender also showed 12.31v

if there was any voltage drop in the big3 wires it was a fraction of mV

hooking up the AEM wideband showed a .15 - .30 in voltage drop (can't remember the number at the moment

car running the voltage was at about 13.8 (in car same test points)

turning on the lights dropped volatge to a little over 12 volts, turning them off bounced them to above 14 then settling back to 13.8 volts, turning the heater full blast also keep the voltage low with no increase

hooking up the AEM gauge with the oil pressue sender disconnected cause the oil psi gauge to start swinging like crazy (I have a video I will post later), hooking the sender up showed less the 10psi, then removing the AEM gauge showd 35psi (warm day, idle)

and of course turning on the headlights and then the heater made the oil psi gauge drop a little each time (little less then before due to cleaner wiring)

any suggestions?