Hey everyone I have 94 ls400 I was driving down to Taco Bell and as I was leaving the drive through I put tried to give it some gas. It started shaking pretty aggressively and no matter how much gas I tried to give it the car wouldn’t go above 20mph I drove home and looked under the car because it started smelling like something was burning when I looked under the cats were bright red and tons of smoke as well



any help is very much appreciated in advance

 

Okay so I had the same problem and it's pretty hair raising when you see something like that. In my circumstance the corrective action was buying a reman ECU it was toast I even sent it to a diagnostic company to confirm so I got a denso remanufactured ECU put it in and all my problems were solved. In mentioning the denso re-man ECU the part # is the same as yours plus at the end of the part number there is a -84 on the part number which tells you that it has been reman from denso which I suggest highly it was like magic all was cured

 

There are a lot of threads online about this

First, are you getting any check engine codes?

In either case, we know your car is dumping fuel excessively. It's time to check the engine coils, both the right bank coil (in front of the engine) and the left bank coil (down on the side of the engine. You have to remove the battery to get to it)

One of your coils might be dead, leading to half the cylinders not running and lots of excess fuel being dumped.

Coil testing:
https://www.clublexus.com/forums/ls-...l#post11357643

FYI - the connectors get brittle and love to break. They are replaceable

 

I had the exact same problem I have a 93 LS 400 so I learned that my ECU was no good I replaced it with a rebuilt denso unit got it on eBay.
The rebuilt denso unit as a part number with a designation of -84 at the end of the part number which tells you it is rebuilt by denso That's important. I am now enjoying my car it totally eliminated that problem.