CaliRx300

So my rx started having issues in the freeway. Once it reaches 60mph car won’t go into correct gear and struggles to maintain speed, feels like it switches into higher gear and slowly Boggs down. Rx drives decently on local streets until it tries to climb a steep hill. At a steep hill it acts the same way as if it’s on the freeway. No CEL on, no pending CEL on. Took it to a trusted mechanic he said to take it to a muffler shop to find a solution.

I spoke to a Toyota tech and he said aftermarket options don’t work out well and the oem cats are approx $700 each.

im considering searching junkyards (pick a parts) to see if full exhaust systems are available but this path is time consuming.. and I have a feeling they are already parted out or in similar condition (my speculation/ assumption)

as this car is used as a daily driver I need to figure out a solution ASAP.

any advice would be greatly appreciated. TIA

my rx is: 2001 rx300 fwd silversport mileage 493,445.

maxSteel

I put in a Walker cat in 2017, no problems with it

sktn77a

iTrader: (2)

How do you know its the cat? Could be a whole host of things. Have you connected it to a code scanner?

CaliRx300

I will reiterate… “No CEL and No pending CEL”

if I didn’t scan for codes I wouldn’t know there weren’t any pending CEL.

So I called a few muffler/cat specialist shops and one specialist said he would charge me $200 per cat meaning $600 to figure which cat was clogged. I politely said no thank you and hung up… smh.

So I sat there thinking my mechanic said there is a clog and I realized using logic that there is nothing that really could clog the 2 cats near bank 1 and bank 2. If and or when a cat due to old age (wear & tear) or if the honeycomb so happen to break apart regardless of which front two cats this took place the only place that would clog due to pieces falling through would be the cat running underneath the vehicle right before the muffler…. So I drove over to a nearby muffler shop told the shop to cut out the cat and weld a straight pipe in place…result? My Rx could breathe and let out exhaust freely on the backend!! Not only did this fix my loss of power at around 60-65mph, my Rx was ALIVE!! I kidd you not with nearly 490k miles on the odo… this car felt like it was given new life! Born again?

Now some of you may think or say, but u have no cat now! I got this car to pass smog literally less than 2 months ago, so I technically have 2 years? Until I’m due for another smog check.

when the time comes, I will probably take the carb legal walker after market cat solution route since this has been the only advice shared.

But man no joke the Rx is driving great! Much better than before i started having this issue. When I took a look through the cut out cat it was clear that the cat was clogged since when holding light on one end and looking through the other end, one could barely see any light coming through. Almost none at all.

Also to add ive been driving with a straight pipe for almost a week now and gas even gas mileage as increased! On avg the car is getting 18-19 miles per gallon. Before I recall the car getting 15? 16? 17 at best if I was driving extremely conservatively. Overdrive has a nice pull when passing on the freeway, throttle response really has a nice pull.

I hope if anyone has similar issue with car starting to bogg down, or literally gradually losing power when under load (going up a steep hill), or not being able to maintain speed limit of 65 on the freeway while car feels like it’s in the wrong gear… If you have NO CEL or pending CEL.. go straight pipe it!! This costed me $90 at the muffler shop btw.

CaliRx300

As I mentioned in my original post, there are no CEL and no pending CEL which would mean I connected and scanned for them.

so I called a “reputable” muffler shop and he quotes me $200 per cat to “diagnose” which cat is clogged. Thought he could hustle me… hell no I’m not paying $600 just to figure out which cat is clogged. So I thought for moment.. logically the 2 cats near the manifolds (bank 1 n 2) have nothing before it to clogg I thought to myself.. if anything due to age n wear n tear (490k miles) IF a cat is clogged it has to be the one underneath the car… following me? I went to a small mom n pop muffle shop discussed with the owner there my logic and he absolutely agreed with me. Since I just passed smog approx 2-3 months ago, I told the shop cut that cat out and let’s straight pipe it. I have 2 years until I’m asked for another smog check sooo by then hopefully I can figure out a solution…an affordable one. Holy crap.. straight piping it literally brought my Rx back to life. It no longer had the issue of bogging down or struggling to accelerate. So yes, straight piping it solved my problem.

I’ve driven around for approx 3 weeks now, trip computer is telling me I’m averaging 18.3 mpg. No CEL however I did see a pending CEL this time around. P0420 efficiency below threshold bank 1.

any tips? Tia

salimshah

Not sure I am helping you but for general info, vehicles in Texas after 25yrs are considered antiques and do not require emission testing.

Seems like the first shop you went to, only wanted your business if you pay them extraordinary price. The procedure would have been decoupling in segments. Flanges are there but the fasteners can give you a decent fight and the shop may have to spend 30 mins tops on each connection and install new gasket and fasteners.

The other thing to weigh is are your bank 1 & 2, run different? Bad oil ring in only one bank can lead to early demise of bank 1 pre-cat. If all 6 cylinders are same/similar than both precats will be in similar condition.

Did you price the Walker parts?

Salim

Oro

Our ES passed emissions (sniff test - actual test) w/o cats. To defeat the CEL I installed spark-plug non-foulers in front of the 2nd 02 sensors, no light anymore. You can drill the non-fouler out to 1/2” or cut the sniffer cap off like this:

https://www.corvetteforum.com/forums...ot-needed.html

CaliRx300

wow really? I’m going to have to try this then. So spark plug non foulers on both 02 sensors located near bank 1 & bank 2?

CaliRx300

could you please shed some light on “bad oil ring in only one bank” please?

im assuming both precats are no good due to age and mileage… (purely my assumption)

if I were to go down the walker parts route, do I just make sure I’m using carb mentioned parts?

thanks salim and everyone else for sharing ur experience and advice!

Oro

You put them in front of each downstream sensor, S2B1, S2B2. You can get a deal off alibaba and not have to drill the kits off the shelf from O’Reillys, etc.

Or get the 18mm kits from the stores. options are to drill out 1/2” to fit the stock sensor tip, or take a dremel, cut the steel tip off the sensor (the sensor is inside, it’s not the steel outer tip you see), and then it will fit in w/o drilling. You can google all this so I won’t get specific, but it’s not hard.

It works, the CEL will go off and, honestly, the car will still pass a sniff test. Ours did. The Toyota ECM logic on this is crazy sensitive, it trips way before degraded cat efficiency actually falls below most legal emission standards.

I have an Acura SLX (Isuzu Trooper). The cats failed so badly the internal material crumbled, blocked flow. Cleared out, but CEL light for cat efficiency never tripped. Passed sniff test no problem even with broken cats.

salimshah

My suggestions were to help diagnose.
I would sequentially decouple exhaust from the back to the front. Once you reach the split then the problem is localized to a bank and pre-cats.
Oil in exhaust is the major reason for clog. Rich exhaust with unburnt gasoline over time is the other. There are ways to recover from oil coated cat. But I am getting ahead of actual diagnosis.
I have no personal experience with Walker parts, and all I know is they are cheaper alternatives to the OEM.

Salim