Before the P1519 code, you had two likely issues:
1) Worn-out/lazy upstream sensors - both of them
AND
2) An intake vacuum leak. Usually caused by the PCV valve/hose or those crappy intake manifold gaskets which always seem to fail.
Sounds like the boys at that parts store were pretty clueless. A P1000 code isn't a scanner issue, it's an indication that the car's computer had been recently reset and that it had not completed all its diagnostics, some of which take several drive cycles and some of which require very specific operating parameters to be in place before the test will run.
Steve
