Hi,Did read default codes and this list came up, could it be just bad connection / bad wireing? or should i buy new sensors?
Also it has occurred when I run with light gas (1600-1800 rpm), the rpms suddenly drops like 200-400 rpm and when I lightly press the gas pedal bounce they bounce back up, it feels like a small jerk so i know something has happend.
Car has also been shut down a few times while driving, the rpms are dropping to zero and that’s it. when i start the car starts like normal and driving continues. This one (year 1997) has been corverted to run ethanol, but now we have wintertime so i use normal 95 or 98 octane. Fuel consumption has been increased...mayby? hard to say since its wintertime

 

1997 LS400?
Mileage?
Are pre catalytic Oxygen Sensors, ECT Sensor and throttle position sensor original?
What is condition of vacuum lines and PCV ventilation tubes (both banks)

Then there are tune up parts to consider...
distributor caps, rotors and sparkplugs.

MAF sensor condition?

 

Yes, it`s LS400 -97 mileage are 304000km /189000ml and all sensor are original. There was few dried tubes what i fixed with vulcanization tape just until it`s sping itme and little bit better conditions to do wider maintance. All together i didnint see any clear break there.
MAF sensor condition...i dont know how to calssify it but i have gently puffed dust off.
Tune up parts, do you mean that i shoud consider them or...?

 

After 25 years radial electrolytic capacitors in ECU are failing.
Do you know whether your ECU capacitors have been replaced?

 

i would think they were original. How do faulty capacitors occurs themselves? I have heard that just by looking them one can not say are capacitor ok not ok...

 

Here...

See:

https://www.clublexus.com/forums/ls-...capacitor.html

 

I Own a 1995 and a 1998 LS400 with original capacitors i ECU and no issues (yet).
Sweden where I live and Finland Where OP live is cool climate countries with yearly average temperature about level of a descent fridge...and mostly short cool summers. This seem to make the ECU capacitor issue being less frequent. It could definitely be The ECU issue but less likely than if it had been a Southern USA car.
The Catalytic converters may suffer if you run the car with bad mix controll . A O2 sensor problem perhaps ?. Changing O2 sensor is inexpensive if you buy a third party sensor.

 

Dude....

A Capacitor Engineer at Nichicon informs radial electrolytic capacitor life is 16 years...

Seals fail and slowly, but surely, electrolyte leaches onto circuit board, which, if not caught in time, destroys circuit traces beyond practical repair, which suggests the only practical way to catch this in time is to be proactive.

ECU Capacitors 1990 - 1997 LS400 are more problem prone than 1998 - 2000, but all should be replaced.

Just recapped a 1995 SC400 ECU.
All capacitors tested bad and exhibited signs of leaking...with one bad trace due to leakage..

 

Actual expereince is most valuable of course Yodaone. I do not doubt you have that.
However the statement that life expectancy is X fixed years is missing a major piece of information. The life is typically strongly temperature dependant. Generally speaking expected life is typically doubled for electrolytic capacitors for every 10 Celcius or 18 F lower temperature. Hence climate, dark car outside in the sun or a cool underground garage must really matter.
If it was easy to get this done as it seems to be in the US I would have done it already.
Here in Sweden we have no companies that have expereince with these swaps and the high temp good stuff were on partial perpetual backorder when I tried to buy them a few years back .
However I do realize that I should prioritize to get this done . My daily driver LS400 is now 26+ years old and that is pushing it....