95 Ls400 Intermittent Vibration

[Marklouis]

Hello all, fairly new member here. I purchased my 95 LS400 3 months ago - started noticing a vibration in the engine at 1500 RPM to 2500 RPM. changed Timing belt, plugs, caps,(i was very careful with the cam sensors) and rotors - reset the EFI and MAIN in the main fuse box under the hood - the issue has subsided slightly, but you can still feel the vibration in the engine at the same 1500 to 2500 rpm ranges - question is does the timing need adjusting any,and if so how to do it? i'm thinking the 95 up LS400's were self adjusting on timing, but i thought i would ask the experts first.

[Marklouis]

I had a code thrown at me Through OBDII reader stating the 1st oxygen sensor on the right bank needs checking/replacing. i will follow through and see if that stops the vibration.

[MR. LEX]

You changed everything but the ignition coils. That right there is the one thing that is stopping you from a full tune up. And the timing self adjust itself 95-up.

[Marklouis]

you are absolutely correct - i need to test the coils to see if they are within specs and replace if need be - thanks!

[MR. LEX]

you are absolutely correct - i need to test the coils to see if they are within specs and replace if need be - thanks!

Hey let me know how that works out for you.

[yoichisoma]

Hey,

If the vibration you are feeling is vibrating the whole cabin-- Like a vibration that causes the passenger seat back and head rest to vibrate, then you need to change the two engine mounts and the transmission mount. Not very easy but I did it. Took a whole day. Unless the check engine light is on it is highly unlikely that anything electronic/ignition is wrong. The engine computer in the 95 can be troublesome. It may cause jerky acceleration/deceleration/shifting. A big jerk can be felt letting off the gas at certain speeds and around the parking lot. It can also stall and have low RPM at Idle. Call around a junkyard for a revised ECU and install that. Get the ECU part number from lexus and do a google to see who has one. It has worked wonders for me. My 95 is so smooth now. I also changed all the suspension arms and shocks up front. Unbeleivable difference. Drum tight. Don't get carried away, but little things can get irritating in this car because you can feel and hear everything.

yo

[Marklouis]

Hey,

If the vibration you are feeling is vibrating the whole cabin-- Like a vibration that causes the passenger seat back and head rest to vibrate, then you need to change the two engine mounts and the transmission mount. Not very easy but I did it. Took a whole day. Unless the check engine light is on it is highly unlikely that anything electronic/ignition is wrong. The engine computer in the 95 can be troublesome. It may cause jerky acceleration/deceleration/shifting. A big jerk can be felt letting off the gas at certain speeds and around the parking lot. It can also stall and have low RPM at Idle. Call around a junkyard for a revised ECU and install that. Get the ECU part number from lexus and do a google to see who has one. It has worked wonders for me. My 95 is so smooth now. I also changed all the suspension arms and shocks up front. Unbeleivable difference. Drum tight. Don't get carried away, but little things can get irritating in this car because you can feel and hear everything.

yo

Wow..we need to talk..you exactly described whats been going on with the jerking and low idle at times (A big jerk can be felt letting off the gas at certain speeds and around the parking lot. It can also stall and have low RPM at Idle.) - the check engine light is on, but only for a faulty o2 sensor right bank. i really did figure i needed to change the engine mounts and tranny mount, but the ECU i never would have thought! is this a common issue for the 95 LS? is there a repair procedure for the ECU maybe - like solder contact points or something? Yoichisoma you have really made my day thanks so much!

[silvermistLS]

hook it up to a computer see about codes... check TPS sensor.