1995 Toyota Corolla Flickering Engine Oil Pressure Warning

I forgot to add this to my question earlier concerning this same problem but to fresh your memory about my question i will start over.I have a 1995 Toyota Corolla DX with 220000 miles and just recently got it out of the shop. Items that were repaired/installed were:timing chain,water pump, brand new fuel tank,and it was leaking oil so a head gasket was replaced also,door handles on driver-side(in&out).I noticed while i was driving my car the Engine Oil Presssure Warning Light was flickering on and off and there were also long period at times when it did not flicker until i hit a bump in the road or stomped my brakes.I stopped and checked to the oil several times and it showed to be full on the dip-stick.After doing this for a few minutes and as i began to crank my care back up the Enging Oil Pressure Warning Light flickered again but briefly and as i traveled down the road it began to do the same as before.Could this be and electrical problem or is it extremely serious than that.