I recently purchased a 1995 LS400. When I test drove it, no issues. When I was driving it home, I was getting on the highway, kicked the accelerator down, and the car started sputtering and jerking, almost like it was running out of gas. It stopped when I let off the accelerator. No Check Engine light. The next morning, exact same circumstance with the same result. Later in the day, I took it to my mechanic to check out. I duplicated the problem, but this time, it sputtered no matter what the speed. The timing belt, water pump, plugs, wires, TPS, MAF sensor, fuel filter, and fuel pump were all recently replaced. Still no codes. Any ideas where to look? BTW, the check engine light does not light up with the key in the on position. Will this not allow a scanner to give code due to break in the circuit?