I want change manifold and put headers to1990 ls400 lexus

1995 Lexus LS400 specifications, information, data, photos ...

www.carfolio.com/specifications/models/car/?car=23507
1995 Lexus LS400 automobile specifications & information. ... The Lexus LS400's engine is a naturally aspirated petrol, 4 litre, double overhead ... 4 valves per cylinder... bmep (brake mean effective pressure), 1171.5 kPa (169.9 psi ).

NO JUST FILL GEARBOX LEVEL AND CHECK AGAIN AFTER RUNNING ENGINE

possible its just your injectors.

Bank 1 sensor 1 --- on left side of engine in exaust manifold .
Bank 1 sensor 2----- on exaust system near converter
Bank 2 sensor 1----- on right side of engine in exaust manifold
Bank 2 sensor 2 ----- on exaust manifold near converter

How to set the timing on a Lexus LS400 when changing the timing belt

Disconnect the battery.
Disconnect the wires from the starter.
Unbolt & remove the starter.
Bolt the new starter into place.
Connect the wires to the starter.
Connect the battery cables.

there located on top of engine under the cover thats says V8 FOUR CAM 32, 4 S.P. on each side,remove both covers and its easy access after that.

Not too bad. Not much room, just enough to drop the starter. It is probably easier to go up through exhaust if you can get your exhaust shield off the manifold .

well your best bet is take it to the lexus dealer to get your oil changed and just tell them you just got it and you would like it looked over good trust me as slow as shops are right now they are gonna do a good inspection hoping to make money.. lol but make sure you go to the dealer cause they know what the commen stuff ya know