240sx engine low idle, stalling

[crystalflash]

A few months ago, I purchased a 91 240sx from a family friend. A few weeks later it started having a really low idle (3-400 rpm) and now it is so bad that it will often stall out on me in traffic. Living in Jersey, you can imagine what it is like dealing with the most impatient drivers in the U.S. Although I am not the most mechanically inclined person when it comes to dealing with cars, given enough time and the right tools (and whatever help you guys can provide) I am sure I can fix this problem. I have already changed the O2 sensor and shortly the PCV valve as well. If there is anything else that couold possibly help me to fix this problem , I would greatly appreciate it.

Thank you.

[navysnail]

do a search on how to check your MAF.