I have a 1990 LS 400 that stalls, only when warmed up. It starts just fine and runs like a smooth champ until it gets warmed up and then the fun starts. It has high mileage, (280K) but has been pretty well kept up.
I originally thought it was because of something in the gas, because it seemed to start stalling only when the gas was under a quarter of a tank, so I put some gas treatment in the tank which didn't help much, if at all.
The weird thing is that initially when it acted like it was going to cut off, I could put more gas in the car and it would run just fine again. But now after a week or so, it's stalling every time the car warms up regardless of the amount of gas in the tank.
It cut off completely while driving a couple of times, but it always started right back immediately like nothing was wrong. But it would do absoutely nothing when I pressed the accelerator, as if it's out of gas
I remember reading a thread about the "limp mode" on the LS and that's exactly what has been happening...it has never left me stranded, but it "limps" home going no faster than about 20 MPH after acting like it wanted to cut off, then 20 MPH; stall, 20 MPH, stall back and forth.
It also fails to rev above a certain RPM, when I put it in neutral or park and try to rev up the engine. Very frustrating! Any clues?
