UltraLexx

This problem is worrying me. I few months ago my 93' LS started to shift erratically and became a bit sluggish. A code 25 came up so I figured it was the O2's and left it for the time being and I'll just live with the crappy MPG for a while. Yesterday I had the oil changed at Wal-Mart ( I know what your thinking stupid me) A day later I went to vacuum out the interior and left it ideling for maybe 5 min. got back in and as soon as I put it in reverse I felt something was wrong immediatly. Now the car has zero power barely idles, won't go more than 35 MPH and used 1/8 of a tank to go 6 miles. There was never any CEL.
I felt it was time to change the O2's So, I overnighted 4 new sensors. Well my car didn't even have enough power to go up the wheel ramps. I changed the sensors and nothing changed still has the same problems.
I lifted the hood and the sounds were not to reassuring especially from behind the motor up around the intake manifold. Sounded like a huge air leak but not too sure.
I just replaced the air filter and use Mobil 1
Any help is needed, this is my everyday driver.

GRAND_LS 4

iTrader: (2)

Please dont Neglect the O2 sensors, because your cats will pay the price. Havent had that problem before, but I heard about it a few times. Search for "limp mode" its been dicussed here a number of times, so you should find a lot of answers.
If my memory serves me right, when somethign goes wrong, the ECU jumps into limp mode to protect the engine from any number of things.


Oh wait, i think i remmeber now, after you let the car idle, what happens is that the cats heat up badly because you neglected the O2 senors. I hope you dont have to change your cats now, thats why you shouldnt neglect the O2 sensors. When the cats over heat, the car gets VERY sluggish and REALLY REALLY slow. So let it idle, then you should see them cats glow red and over heat. Change O2's ASAP.

UltraLexx

Hey Grand, I changed the O2's the very next day.
Do you know how to clear the "limp mode" and or diagnose burnt cats. The air sound I was hearing is seems to be coming from the exh. manifold/cat area. Perhaps I blew the gasket there? I found cats for $127 a piece.
I don't want to waste the money if it's just in this limp mode. Any more help would be great

GRAND_LS 4

iTrader: (2)

Try and reset the ECU by pulling the fuse for 20secs, or pull the battery cable for 15mins. If same symptom turns up, check for exessive heat coming from under the car, in which you will know its your cats.

UltraLexx

Update: Ordered new Cats. I just took off the old ones and I didn't find what I was expecting. The left one (passenger) there is about 15% blockage and the right one looked clear. I did the test to heat up the cats and the left one got very hot within minutes.
Soi when I removed the converters I was expecting an obvious blockage, can a bad converter be only 25% blocked and can one semi-clogged converter cause the problems as described above?
Thanks to all that reply

Rich

PERRYinLA

A similar discussion dealing with the same symptoms (but with a much more informative title) is going on right now in the SC300/400 forum:

https://www.clublexus.com/forums/performance-and-maintenance/94079-sudden-loss-of-power-catalytic-converter-glowing.html

UltraLexx

Well after all the troubleshooting I did and labor I finally found the culprit. It was the right bank coil wire, The wire was almost shredded in half. I put the old cats back on and now waiting for Toyota to find a replacement. On my Jeep this would have been a simple find and fix.
I learned a valuable lesson, Always check the simple stuff first. Because it was a Lexus I held the problem to different level.