I have a 1993 Lexus LS 400 and have recently been experiencing the following problems:

The RPM drop very low
- Sometime the Engine just shut off
- The check engine and the TRAC OFF light turn on
- Smell very bad like it not burn all the gas
- The muffler is build up with black stuff very bad
- It run fine sometime and just shut off the engine when stop at the traffic light.
- The AC is not cold anymore

If anyone has experienced the same problem, pleased share some of your solutions...Thanks!!

 

MikeW,

That's crummy that you're experiencing those issues. You might want to start with the Check Engine light and try to see what codes it's throwing.

How many miles do you have on it? What's the history of work on the car?

 

The car has 147,000 miles. I ran the engine codes and it showed code "47" (Sub-Throttle TPS). I replaced the TPS but the problem still exists. Sometimes the car runs fine, but recently the problems have been becoming more severe. The car has a great maintenance history, but this problem is very perplexing.

 

Definately pull the codes first to see what comes up and that will narrow it down alot. Here's how to get the codes; http://www.lexls.com/tutorials/intro/codereading.html
With the gas smell it means it's running rich, mine was like that with a bad AFM but I didn't have the engine light until I unplugged it. Here's how to test the AFM, and a couple other things; https://www.clublexus.com/forums/sc-...on-issues.html

You posted as I was typing. Did you clear the codes after you changed the Sub-TPS? I doubt the sub-TPS would make the car run bad seeing how that only works with the traction control.

 

Yea i cleared the code by removing the neg battery cable for approximately 30 sec. I will use the links you provided to run the codes again to see if i missed something.