My car idles so low that while at a stop light or in slow traffic the oil pressure gauge needle sometimes dips to the 0 mark. I have to give it a little gas to prevent the car from dying. The oil level is correct. Oil pressure is fine when I put on the gas of course. I recently put in a new fuel pump and opti. What is the most likely cause?

Thanks

 

Could be as simple as a bad oil pressure sensor. You can always attach a mechanical gauge to verify your oil pressure.

 

engine, fuel injectors and or ICS gummed up? Try sea foaming the engine, or GM TOP END Cleaner, same stuff

 

What is the idle speed? Stock programming for your A4 is 550 RPM.