Oil Change issue

[Blantz]

I just recently had the Oil changed in my 1991 Vette. A few days later I saw that the "Check Gauges" (Not the Service Engine Soon Light) came on while at a stop light. When I'm driving, the oil pressure goes back up to a normal reading and the light doesn't come on. It's only while the car is ideling.
The Oil that they put in was Mobil 5W30 Synthetic, which is what I usually use when I change the Oil. The Car has about 85,000 miles on it. Would it be a good idea to switch to a 5W40 Synthetic Oil, or is it possible that the Oil change has nothing to do with what's going on with the Oil Pressure? it just seems strange that this happened only days after the Oil Change.

[Rimmer]

It would be better to check the oil pressure mechanically, it may just be a bad gauge. (hopefully) Is the engine making any new noises? The heavier weight oil probably will not help if it's a mechanical problem. It's better to diagnose the problem before doing anyhting else.

You could check the filter for blockage. A lot of possibilities?