91LS400LEX

UPDATE - I went back out, started it and it was still doing it, but I let it run for about a minute and it cleared out and was running fine. Also started normally after. Must have been where I started it yesterday I didnt let it warm up long enough before shutting it off.

I went to leave in my car (1991 LS400 with 225K) this morning and the starter sounded funny.. almost as if the car had low compression.... it was like it was missing when it was cranking. When it started, it made a funny sound as the RPMS went up and then it started shaking, missing, pouring out smoke that smelled like gas, etc!! I shut it down and took my other car to work. So finally the LS has let me down again. Timing belt was done only 24K ago. It was running perfectly yesterday.

The gas is less than 1/4 tank... I was thinking maybe water in gas... bought gas treatment, came home, started it again and its doing the same thing and it sounds bad. I am not sure what has happened. The CEL (check engine light) is not on, so its not like its tripping any codes.

Thanks for any help.

91LS400LEX

UPDATE - I went back out, started it and it was still doing it, but I let it run for about a minute and it cleared out and was running fine. Also started normally after. Must have been where I started it yesterday I didnt let it warm up long enough before shutting it off.

trukn1

Possibly ignition coils. Mine had alot of the same symptoms when they went bad on my 92; except for the starter noise. Strong smell of gas, the shaking, the missing, the smoking were all common symptoms. I was actually driving mine at the time and the car would not even get out of it'sown way. Changed the coils, and no more problems.

jasonburt

Have your injectors tested either on a bench or with an ocilloscope. These older 1UZ's have had injector coil issues under the throttle body where it gets hot.

Amskeptic

It is also a common and harmless symptom of many fuel injected cars that are started briefly in the winter and driven across the street or up the driveway, they will have a brief plug flood-out especially if the cold start valve was triggered. Noticeable primarily at next start. The rules of this engagement are simple: keep it running, drive it, and have it warmed up before parking it.
Colin

MattLS400

Hey, after having executed a Diagnostic on my 1UZ, no trouble codes are appearing.
However, when the temperature gauge reaches at the half-mark level (or otherwise, when the vehicle is left on for such a time that the engine gets hot, which is on average somewhere about the said half-mark level)I am currently experiencing a rough idle followed by shutting off of the vehicle.Nonetheless, it starts back perfectly afterwards.

I have changed all 8 injectors, oil, engine crankshaft sensor and fuel filter inside of the tank. But the problem still persists. Any assistance would be greatly appreciated.

LScowboyLS

As you guys could have guessed, my vote is on failing ECU capacitors!

but first I would replace the following:

● gauge temp sensor with the genuine Toyota part
● engine coolant temp sensor with the genuine Toyota part

these can only be purchased at a Lexus or Toyota dealership, but some dealerships sell online at around 25% discount

these two sensors are located right beside each other right behind the passenger side coil, kind of under the plug wire tray, a little behind it

LScowboyLS

This is unacceptable in a modern car, I have an '86 Nissan 300ZX, '96 Acura RL, '96 LS400, '92 Honda Accord, '86 Toyota truck - none of them have ever done this, and no well designed fuel injection system needs to be parked "warm" - if it does, it is either malfunctioning or a pretty dumb design such as the American or French car companies might come up with

jcp2k

My 92 did the same thing once. I thought the motor finally blew but I was wrong, I let it run it also cleared out and been running fine since then. I believe this happened due to a injector either leaking or stuck open. So it made it misfire, smell like gas and, cause black smoke cause it was flooded. Or I could be wrong