TruongJL

anyone having problem with their 1UZ?
for some reason the car has a minor miss.
I've replaced everything.
spark plugs
cap n rotor
wires

checked injectors voltage and replaced all 8.
also checked the computer too

RA40

iTrader: (6)

LScowboyLS is going to ask if you did the ripple test to check the ECU.
https://www.clublexus.com/forums/ls4...-by-yamae.html

If not the big thread on the ECU fix:
https://www.clublexus.com/forums/ls4...capacitor.html

Check the vacuum lines, on these old cars the loss of vacuum especially leading into the intake plenum are important.

The coolant temp sensor threads are also part of a nice running car.

LScowboyLS

well heck - I can clock out early tonight!

please tell us the year of your LS400 have you dumped the codes?

TruongJL

thanks
2000

LScowboyLS

can you scan the codes on this car? - either get an inexpensive scanner like this one or else run it by Advance Auto Parts, O'Reilly, Autozone, etc. most chain auto parts stores will give you a scan and printout of your OBD-II diagnostic codes for free!

we need to know the codes

PS - have you cleaned the throttle body and VVT system?

Boxcuta

MAF or ECT

YoshiMan

You said you replaced the "wires"?

2000s don't have ignition wires per se, but individual coils on each plug.

One of those coils could be dying on you.

I don't know anyone else who owns an LS, but I know numerous people with RX300s that experienced failed coils, which in turn caused the engine to just run like hell. Seems to be an epidemic with the 1MZ-FEs!

LScowboyLS

whoa! - good catch!

I am sleepin lately - lol

they don't have cap & rotor either - lol

PureDrifter

iTrader: (10)

this makes me think you're either lying about replacing everything, or need to go check the invoice your mechanic gave you and re-read it.

sounds like an ignition issue in a single cylinder. Likely a dying coil pack, spark plug, or the wiring to one of the packs.

LScowboyLS

there is no way on earth you could possibly determine that from the extremely limited and apparently erroneous information given by the OP - at this point we have no idea of what has actually been done, or any diagnostic codes, so how in the world have you traced that down to just a couple or three possibilities? - I can think of about 25 or more!

timmy0tool

iTrader: (7)

when a car is misfiring, i always replace the plugs first. it clears up 90% of the time. this is usually the case with direct ignition cars, which your 99 is!

PureDrifter

iTrader: (10)

Those aren't the only possibility, just the simplest and therefore most likely.

^this. As it is an individual coil pack car there's a very low chance of >1 cylinder having an issue unless it's a cam sensor issue.

YoshiMan

I'm just glad i wasn't Mistaken! I realized like ago i am not nearly as familiar with the gen 2.5 LS's as i would like to be!

TruongJL

IC. GOOD points but let me rephrase if i may

7 months ago my car started missing. small but slightly noticable at idle.
suddenly after cruising on the Interstate it completely DIED.
lifted the head and found out, Cylinder 7's valve broke (Somehow i dont know) and cause alot of damage.
Got a used 1UZ from LKQ with harness. installed, ran good for a bit then suddenly the miss returned.
There for i suggested the computer. took it out and had it rebuilt from (ForeignECUrepair.com ) they have done a few computers from me for other various cars.
Flashed it and Problem still remain.
changed out plugs to NGK iridium, all new coil etc...

TruongJL

i dont mean to offend anyone by LYING about my curiosity, but i highly doubt im BSing, when my car isnt running right and i wanna ask professionals