Nissan Repair: Warm weather stalling, throttle position sensor, oxygen sensor

Question
MY 1994 Sentra runs fine in cold weather, but as soon as the weather and the engine get warmer it starts to stall when stopping,  especially if I stop abruptly. Ive had the oxygen sensor replaced, and the fuel filter. No change. My mechanic says it wouldn't have anything to do with a simple tune up (like changing the plugs, wires or distributor cap)....with such a specific symptom that only happens when the temp is over 40 degrees, or so,  shouldn't it be a simple problem for a mechanic to identify?


Answer
I would be looking at the fuel curve and that would lead to the throttle position sensor.  When it is hot outside the engine will run leaner and if the throttle position sensor is getting old the contacts are probably corroded and this leads to a slow response.  That would be the first place I would be looking.  You did say that the mechanic did not think a tuneup would do the job and you had a new fuel filter.  Have you had the injectors cleaned?  I would atleast check the fuel pressure before I bought a throttle position sensor.