Tony (JP)

Well first of i'm new to the whole Lexus ownership but not new to Toyotas at all I've owned a turbo'd AE86 hatch along with a 1jz'ed MK3 supra and a 1992 Toyota Cressida I've had for awhile now.

I pick up a 1993 LS400 about 2 weeks ago in mint condition with 107K original miles the owner was a victim of the Weinstein Madoff scheme that went down a few months ago and owner was forced to sell. All I did was changed the battery terminals upgraded to an optima red battery changed the P/S fluid and threw on some 8000K HID's. So anyway the car was running fine but now coming across some problems, first thing im driving the car with the A/C on and if I turn it off as soon as I let go of the gas the RPMs drop all the way down and shuts off. If I turn of the A/C while stoped the RPMs drop and rumble for a sec then returns to normal.

Now second problem, this happened yesterday im coming back from a trip then all of a sudden the check engine light comes on and the TRAC shuts off then the RPMS start to jerk around 2k RPM. So whatever I pulled into a truck stop look under the hood and couldn't spot anything so I try to jump back on the highway and cars is hardly moving I have the peddle to the metal and nothing it very slowly starts to pick up speed.

The Reverse and L gear work fine, the fluid is a little dirty but nothing I would expect to be causing the failure I also check the dipstick to see if there was any metal shavings and nothing.
Sorry if I sound like a newb but im new to this car and don't even have a manual to figure anything out.

vaughn37

welcome.......check your codes first http://www.lexls.com/tutorials/intro/codereading.html

GABE_LS400

first things first open oil cap and stick a screw driver in there and let it fall inside. Then turn the car on and let the screw driver do its magic. This is a mechanics secret, if the motor destroys the screw driver then your motor is in top conditions if the motor slows down then you need to buy a new motor. Eighter way this will tell you whats wrong with your car. Oh almost forgot pour some antifreeze in the gas tank, this will clean out the injectors and make you boost about 20hp more.

Tony (JP)

Alright well still no luck finding the problem so most likely will take it to the mechanics this week. I noticed in the morning the check engine light & TRAC light are off I drive the car with no problem then the RPMS starting bucking and it stalls abit. Anyone think it can be the fuel pump acting up? I know the previous owner ran 87 octane so once the tank ran out I put in one of those Chevron Tecron additives and filled it up with 93. I also noticed now that the car has alittle bit of exhaust tar on the bumper like if it been running rich.

Any guessing what it could be?? the car only has 107K so I really don't understand how the transmission can be going already. plz help!!!!!!

Yotarip

I had the same problem. This past March I bought my 1993 ls400 with 79k miles on her and she ran perfect for about a week after I got it home. Then the problems came. It turned out that the problem was a bad ECU. You should run a diagnostic check and if the ecu does not give you a code then it's a bad ECU. It's a common problem with the early LS400. There are several companies that repair the ecu's and I used this one:

http://www.foreignecurepair.com/rnrlexustoyota.htm

I was very happy with their service and the total cost came to around $250(express service) with shipping. Turn around time was 3 days with express service. I have since put 10,000 miles on the car without any problems.