popcure1

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?

So...it actually ended up being a bad Engine Control Module. Got it rebuilt for $350. Now the check engine light is on and showing a bad knock sensor. I took a look under the intake and saw the lead wire on #1 knock sensor is broken away from the plug completely. Would this cause an intermittent "miss"?

Knock sensors are pretty cool. They "listen" for preignition (knock) and when they hear one, they !Removed! the spark a little to correct the problem. The bad knock sensor (disabled) is most likely either causing a "knock" signal to be transmitted to the ECU and that is unneccessarily retarding your spark, cutting power and going to a default "limp" mode as it cant clear the perceived knock, OR it is never sensing the knocks and is allowing the ECU to advance the timing to a dangerous knock level that will eventually destroy rod bearings and pistons. With todays electronically controlled ignition timing, you need these sensors to work properly for designed performance.

I am getting it reconnected today and will go from there. I really hope this is it...my boss (wife) is questioning me purchasing.

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?

So...it actually ended up being a bad Engine Control Module. Got it rebuilt for $350. Now the check engine light is on and showing a bad knock sensor. I took a look under the intake and saw the lead wire on #1 knock sensor is broken away from the plug completely. Would this cause an intermittent "miss"?

Mine felt as if it were running out of gas, bucked and jerked then lost power. I assumed it was either lean or had lost a coil (1/2 power) Now I believe it was very rich (dirty air filter and MAF) and the ECU cut back fuel, defaulted to "limp home mode" which gave the false impression of lean with half spark. It's a theory, but makes more sense then saying you have to replace 37 parts to make a Lexus run properly. Don't OVERTHINK the problem !

Great advice and I took it. Waited until it got dark, started her up, and found I have a plug wire with an intermittent glow. Tackle it tomorrow and see what happens. Thanks.

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?

Thanks to all who have responded! I will check into everything simple, then go from there.

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?