1999 lexus es 300 cat converter im told its a 2-3000 dollar job. what do u think.

PO420 & PO430 --are worn out Exhaust Converters

You can research any Generic OBD2 Codes on the
internet & learn more than you need to know

A Converter is only good for 12 years & will only pass
inspection MAYBE for 14 years

O2 Sensor Codes are PO170 thru PO 175, so you
may want to study on your own, as you were given
useless advice

im pretty sure it has only one. most vehicles do!

What codes are you getting?

Are they cat inefficiency codes?

If they are than it doesn't matter what the back pressure is. If the cats are no longer converting exhaust gaps into oxygen, CO2, and water than they are bad.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

A constantly blinking check engine light means you have a misfiring engine that is bad enough to cause your catalytic converter to go bad! Take it to the shop... probably means ignition parts and the upper manifold has to come off... and that's no fun! Good luck.

P0420 is catalyst below threshold. It is triggered via the rear o2 sensor (post cat), so you may want to check that sensor to make sure it's functioning properly.

it would be in the interior fuse box some where near the drivers feet or door. there is a key on the cover that should say mirrors

these car are bad at valve cover gasket, the job is about 300-400 dollars
so it's worthed fixing it

according to the manual i have... it has three.... one in the exhaust manifold.... and two in the exhaust pipe..... slightly vauge on the exact location of the last two sensors... but looks like it is after the catylitic converter.

I have a 1999 ES 300 with the same problem. I took it to an independent repair center, (Big O Tires). They ran the codes and it told them it was one of three oxygen sensors in the car. There are two sensors for the engine, (one on either side of the V6 engine), and one for the catalytic converter. The bad part is this sensor is located AFTER the cat. converter, which means it could be the converter, (about $1500.00), or the sensor, (about $250.00). After checking all sensors, it was determined it was PROBABLY the sensor after the converter. I had the sensor replaced and so far the lights have not come back on. Seeing that your car is a 2003 model, I really don't think it could be the converter. If you have been dealing with a reputable repair center, go there. Otherwise go to the dealer and see what they say. If they recommend the converter, push for the sensor. That way you are only out $250.00! Good Luck!!!

There is one before each catalytic converter (usually up right near the exhaust manifolds), and one after each cat (or if you have a Y-pipe exhaust that brings the two sides together to one pipe and one converter, then there's one after that single converter). Why do you want to change them? Have you gotten failure codes or are you having poor gas mileage? Or have they just been in there a long time? They're usually good for about 60k miles, although of course they can fail early. Usually the symptoms are poor fuel economy, running rich (seen by black smoke out the tailpipes and some rough idling, as well as blackened spark plugs), or fault codes dealing with system-lean or system-rich descriptions. Those symptoms are indicative of bad primary O2 sensors (the ones closest to the engine). If your secondary sensor(s) are failing (the post-cat sensor or sensors) you'll trip a check-engine light warning you of poor catalytic converter efficiency.