I have a problem with my1993 Lexus LS400. It doesn't have any power at all. I have had the mass air flow sensor replaced, and new cadlydic converters put on and still no power. It start up without a problem. While running it doesn't shut off. I was wondering if you had an idea on what it could be?

They may fix, but keep in mind that 1994 is non -VVTI and the 1999 is VVTI. (They would have different specs.) Therefore different timing, GL.

have the computer fr-flashed and see what happens

The O2 sensor (2 on V engines) are in the exhaust system pipes before the catalytic converter, the next sensor is the efficiency monitor for the catalytic converter system it looks like a O2 sensor but performs a much different function as far as testing goes. The codes you have follow.

P0420 - Catalyst System Efficiency Below Threshold Bank 1
What does this mean? In most cases it means the catalytic converter is worn out and that is sensed by the catalyst monitor I spoke of earlier.

P0102 - Mass or Volume Air Flow Circuit Low Input
Faulty mass air flow sensor
- Dirty mass air flow sensor (located in the air intake hose to the engine from the air cleaner)
- Dirty air filter
- Mass air flow sensor harness is open or shorted
- Mass air flow sensor electrical circuit poor connection
- Intake air leaks

Sounds like your fuel filter is getting clogged up. Get that changed and it will be fixed. Should be an easy, cheap fix. Hope this helps, James Booth :))

no-- but could mean that the O2 sensor is not correct
it is a common misconception that all of the oxygen sensor are the same
the fact is that even they are known a oxygen sensors there are 2 completely different units
the sensor in the exhaust manifold before the cat converter is in fact a heated oxygen sensor and it's function is to report the exhaust composition so that the ecm can adjust the air/fuel mixture
the other is an o2 sensor located after the cat converter and fine tunes the system after the cat converter has done it's job
if the cat converter is faulty , the o2 sensor will try to have the ECM correct the mixture
the loss of power if it is a cat converter comes from a blocked exhaust system and that is most evident at high rpms or under power

I had the same problem with my 1992 LS400. My Lexus mechanic fixed it by replacing the MAF(Mass Air Flow).

This used to drive me crazy when the weather was hot.

the ls400 had problems with the mass air flow meters acting up. You will have to have it tested because they are not cheap. U can get a used one for around 100.00. They cause the car to boog down while trying to accelerate. Check the wires going to the mass air flow to make sure they are making good contact. I have seen this cause a problem. The mass air flow is located on the hose that goes to the throttle body. I have a good one for a 94 to bad you do not live in texas. leave comment

replace the mass air flow sensor.

you need to get this vehicle scanned by an experienced technician preferably a lexus tech using lexus equipment. this will cost you a one hour diagnostic charge but it will save you money and aggravation in the long run.

Well first run a self test on the computer for trouble codes,l then based on those codes you replace affected parts, but first does it have fuel pressure? how about spark?