warm start problem

Hi
I have 98 passat V6. My problem is that the car won't start when the engine is warm. It starts cold - no problem. I can't stop to fill up because it won't start again. I went to mechanic P0141 code read. Is this code connected with the warm start problem? I had exchange temperature sensor few weeks ago because the car wouldn’t start in the morning (when cold). Than run good for couple of weeks and now there is a problem with warm start. Please help, I have appointment next week, mechanic said that must be leak in the emission system but it will be hard to find.
I read that it could be problem with the gas cup but I checked and it looks good I always click at least four times when I close it.
Please advise.
Thanks,\

looks like you have a o2 sensor problem. replace the rear o2 sensors and front o2 sensors.. Or replace the bank 1 rear o2 sensor (i believe bank 1 is the pass side one)

I am not too sure, but I think you can Ohm the resistaqnce on the two leads, while it's running or not. The one that looks bad (either o or infinite) probably bad. o2 sensor is about $120, if I am not mistaken.
Good luck.