98 LS400 Wont Spin the Tires and Down on Power

[grandpa_spec98]

I know these cars aren’t performance cars by any means, but having a v8 and being on a backroad with no traffic on old tires, curiosity gets the better of me. On a cold day I’m lucky to spin the tires in the dry, and it barely spins in the wet. Doing a brakestand it just sits at 1,800RPM when the trans warms up, but it’ll start spinning during a burnout when the trans is cold. Between this issue (Torque converter?) and another issue I’m having, where the car feels fairly slow compared to how it used to, not like the guys who are reporting 30 second 0-60 times but I’m probably in the high 7s low 8s. I’d like to have the car performing as it used to, what’s a good list of items to consider for a “tune up” as well as returning it to the stoplight squealer it used to be?

[grandpa_spec98]

I do have a CEL for o2 sensors last time I checked the codes, but the light has gone off and come back since then.

[grandpa_spec98]

Coming back to say I timed the 0-60, it’s nine seconds flat instead what I believe was supposed 6.5, so down on power is probably going to be the reason for it not spinning the tires.

[mikaelse]

It seems people typically have reported <6.5 Seconds for 0 to 60 for the 1998 to 2000 LS400 . I checked this on my 1998 LS400 several years ago and as far as I remember that is what mine did too. 

It seems yours is seriously down on power or shifts to early or something else ? .  Mine (Europe spec if that matters)  shifts at 6000 rpm consistently if I floor it .

You may be down 25% on power which is a lot. 
It could be due to several reasons. Not a small thing. A ODB2 scan might reveal something. Does it run lumpy or give you worse than normal gas mileage?.
Could be some seriously off sensor giving a bad signal?.  Some problems like a lot of misfires may give collateral damage to CAT:s and other parts due to overheating etc if not fixed. 
Sometimes problem is easy to fix. I once had a sluggish car that had a worne throttle linkage and barely max half opened. 
 

 
  

[grandpa_spec98]

So, I'll update this thread. Fuel economy was about normal, averaging 28 US MPG, however I did end up losing idle. If I started it, it made no effort to try and idle, it just died. If I gave it throttle, it'd Rev up just fine but die immediately after letting off. Disconnected the throttle pedal position sensor, what do you know, it was idling but now wouldn't rev, and was running so badly a fluid of some sort (probably oil from valve covers) ended up on the exhaust manifold and I noticed smoke from under the hood. Sad that all of this is popping up, I've been told valve cover gaskets and spark plugs might help, fuel injectors, starter might be going bad, ECU is going bad. Sad that it's gone like this but I can't take it to a shop because I don't want to get it towed, and I don't have an exact diagnosis. Considering selling but I bought this car when the market was low so I wouldn't be able to pick up something similar for even close to the same price. Any help is greatly appreciated.

[RX400h]

The first thing any good mechanic would do is look at the codes. I'm sure there are more than one. Only then can a plan of attack be created to access cost and whether or not your car is worth fixing. You should be able to have an auto parts store employee check your codes.

[grandpa_spec98]

There were no codes at the time of taking apart, due to electrical fault from a failing starter. Valve cover gaskets leaking into the spark plug tubes and soaking the plugs are part of the reason of running badly, and probably cheap fuel injectors. Currently have all spark plugs out, valve cover gaskets off and working on intake manifold. My list for what comes next is as follows.

OEM or Bosch fuel injectors

New MAF sensor

New o2 sensors, upstream and downstream

8 new coil packs (oe replacement)

8 new spark plugs (NGK Laser Iridium Plug 4589 gapped at .043)

Valve cover gaskets

Accelerator Pedal position sensor

Knock Sensors

Starter