Autozone told me the code was for small vacuum leak and a large leak. Is there anything I can check?
Also, oil pressure gauge goes up and down between the lines. It goes down half way when at stop sign and runs at the line all the way up when driving...is that normal?

 

I have the same problem with my 01 D I have found dry rotted vacum lines on the right side of the egnine compartment (as you are looking at the windsheild) that go to the evap system and replaced them. This fixed the the problem for a while then it came back. I am confused too. just wanted to let u know what I have tried.

 

Replace the gas cap. I had a faulty one on my Dakota, light hasnt come back on in over 8 months. And that's normal operating range for the oil pressure, as long as it doesn't go into the extreme areas (ie: all the way down into the red zones).

BTW you can check the codes yourself. Turn the ignition key on, off, on, off, on and leave it there. It should read out through the odometer a code P XXX... Just remember not to start the engine when doing that. Saves you a trip to a dealer or somewhere to read MIL codes, though this won't spit out transmission codes.