I have a 2006 LC. I have had this issue four times over the years during hot summer all in the same place going from SoCal to Las Vegas…which is a long slow hot climb uphill. Makes sense. Another two times were in 110 degree plus days returning home from Lake Mead which is about a 40 mile drive. I have since replaced all the items mentioned in my post above. I don’t recall having fuel boil in any of those situations so again makes sense. Just this last winter (so temp was maybe 50 degrees) I did a hard trail at altitude above 8000 feet and experienced the fuel boil effect and slowly vented. Another LC with me experienced the boil also. Neither of us stalled though like the four times I experienced above. So again your description sounds accurate for those long hot uphill drives. In Colorado last summer I spent an entire week at altitude but filled tank to 3/4 with ethanol free gas and no boil and no stalling. Thanks for the detail as I now understand the difference between vapor lock and the stalling.Here's the sign:
Engine runs in higher RPMs, like when pull up a hill. Higher engine RPM signals fuel pump to run at higher speed. Fuel pump runs hotter at higher speed. So the longer time frame we run at higher RPM, the hotter wires to pump and fuel pump become. So ascending a hill, especially a long hill. Is when we see happen most often. Then as we let of the gas pedal (crest the hill and begin descending). RPM drops and so does fuel pump speed. At this point fuel delivery pressure/volume is not enough, as pump slows to much. This almost always is only when outside air temp is hot, especial on a sunny day increase ground heat.
So hills and mountains passes are where accrues the most. But as pump gets weaker with time. Even just short acceleration, than let off gas pedal it may accrue.