Hello all,

We have a 2004 Enthusiast, all stock, automatic with 90K on the engine. Couple of months ago the oil pressure gauge got stuck, and we just replaced it 5-6 days ago. I got brand new pressure switch from Nissan dealership. car also had a big oil leak from oil cooler, and oil cooler gasket got replaced at the same time when we had the switch done. The car also got oil change. All of this was done by a mechanic, and not us.
Today, the oil pressure started misbehaving and the little oil lamp on the dash comes on when car is idling. As soon as you touch the gas pedal, the light turns off. Oil pressure sits at around 15-30, depending on speed, but never goes over 30 PSI. Occasionally it drops to 0. From what we can tell, car runs fine otherwise.
Considering we just had these repairs done, is there something maybe wrong with the new pressure switch/sensor? We are down to one car as it is, we can't afford to just stop driving. Dd our mechanic screw things up?

Thanks in advance!