93 pathfinder emissions help

[ilikeporkchops]

I bought a 93 pathfinder and took it thru emissions
the HC was 3.62,CO was 74.65,the NOX was 1.46
I changed the spark plugs and found a vacuum leak going to the fuel pressure regulator and fixed that.
I took it in today And the readings were as follows.
HC 3.16
CO 21.78
NOX1.34
The numbers I need are
HC2.00
CO.20.00
Nox 4.00
The mass air sensor I think needs replaced ,when I decelerate it wants to die ,even more so with the ac on..
So what I'm asking for is ,is there anyway I can get the readings on the HC and the CO down to the acceptable levels without spending an arm and a leg?

Any help would be greatly appreciated.
Thanks,