Unique P0171 code/engine suddenly dies
 

I have a '99 Protege 1.6 liter and am having a serious problem.

While under idle or driving the engine suddenly and instantly dies. It doesn't run or idle funny, it just instantly dies. When it does it throws code P0171/lean bank 1"

It runs smooth and revs smooth. No discernable loss in power, no hesitation, no nothing. One second it is running, the next it just dies. This can happen almost immediately after cranking it up or it can happen after 30 minutes of driving. In all throttle positions, hot or cold.

I have replaced the fuel pump and air inlet hose. When I replaced the air inlet I checked and cleaned the throttle body. I also replaced the MAF sensor which did not help. Next I will probably replace the 02 sensor in the exhaust manifold.

Any suggestions?