First you say it will crank but not start, then you say it won't even crank.

Your mechanic (it seems to me) should have measured the fuel pressure before replacing the pump (I guess replacing the filter is not a bad idea.)

I suppose it is a REAL long shot, but how old is the battery? Old batteries in these cars do WEIRD stuff.

This does NOT sound like a CPS to me, not at all, after what I have read and heard from others.

Now, why not try this:

Let me google that for you

Odd result, isn't it?

Try googling the OTHER code and you get a rich fuel mixture indication.