My 1990 Lexus LS 400 stalls unexpedly (at any speed).When put in neutral, it starts up and runs fine for a few minutes then stalls again. Why?

check engine temperature could be overheating or you have faulty throttle control motor.could have faulty mass air flow sensor.have vechicle code scan before buying new parts.

Need to check next time it quits,pull a wire and see if it has spark,
I suspect it is a ignition problem,not fuel.

It is a bad (leaky) electrolytic capacitor in the dash board that cost a few dollars. The dealer wants to install a whole new dashboard assembly for big $$$.

Okay you may want to check to see if the sensor on door lock cylinder hasn't fallen off from the lock itself. Pull of the door panels and check the wires at the door lock cylinder. Hope this helps.

Look for a small electric motor near the accelerator cable and near the top of the valve cover.

It's call IDLE AIR CONTROL (IAC) motor.

It's job is to increase the idle when load is added.
Example: turning on headlight,turning on AC.

Testing it is simple.

Warm up you car for 10 minutes.

Locate the IAC motor

turn on loads.....AC,headlights,etc


The motor should move the idle up


If the motor does not increase the RPM then it can be stick.

Try to give it few gentle taps to free up the gears.

It can be clean if your are up to it.


This electrical motor is very expensive. Please handle it with care.

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The other trouble spot are

old accelerator cable

TPS Throttle position sensor

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I will do a simple tune up and gas treatment before starting to replace any parts.


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ignition coil

your abs system is malfunctioning. i would suggest that you take the car to a dealership asap

yes, no problem

have mech ck timing

Hi again,

Any developments with your Lexus?