P0430 2009 Lexus IS350

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Sep 18, 2002
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Location
VA
Mechanic is trying to figure out how to fix my IS350. She said the O2 sensors are working. Cat seems to be working. Can find no leak
or sooty spots in exhaust. She said fuel trim is a little rich on bank 2 (which is where the problem is on bank 2). She says she is gonna
go out and do a highway run tomorrow and see if anything else flairs up. She says she has seen where the cat converter "guts" pull away
from the body once it gets hot and allows exhaust gases to sneak by and throw this code. She has seen switching grades of gas can throw
this code. I only run premium Top Tier.

100K. Denso OEM plugs installed at 76K in 2016.

Just throwing this out here. She is the mechanic the local Lexus "dealership" come to when their mechanics can't figure things out.
She's the mechanic that fixed my '98 LS400 that nobody else could fix.
 
She said sensors checked out fine. Toyota sensors.

She found no hisses, no cracks and no soot.
 
I am no fan of testing a sensor that has 100k and saying it tests out fine.

So, you either have an intermittent sensor that looks good, and/or your your cats are done for. Or, maybe a lazy sensor that looks good?

I'd replace all 100k a/f sensors before swapping in a new OE catalytic assembly. And, with the new catalytics, you're going to want new sensors anyway.

Maybe send the injectors to Trav for a cleaning and test to verify spray pattern, no leaks....

I'd also make sure engine temp sensors work fine and preemptively install new OE thermostat to make sure it gets up to temp quickly. Nothing worse than a bad/slow thermostat and iffy temp sensor reading that all is well too.

Time for:
 
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Mechanic said there is absolutely no rust. No leak. The light has not come back on but fuel trim looks a little whacky on bank 2.
Bank one -1 to + 1. Bank two spending a lot of time -4 or so. No codes or pending codes. She poured a can of BGR 44 in for good
measure. Any ideas? She is suspecting my wife driving short trips back and forth to work may have carboned it up a little???
 
Well, maybe this will help someone else. Mechanic continued to scan and drive the car. This morning she was driving it to pick up some parts and the code came back on. She started checking and found the enginentemp was only 181. She is suspecting bad thermostat that is not allowing the engine to get to normal operating temp which may explain the the higher negative fuel trim.

Apparently, a sticky thermostat would explain why it runs without a code for 6 months and then throws a code every week or so. That was the frustrating issue. No problem for months and then back to back codes for weeks and then no codes again for months.

What cha think?
 
Mechanic said there is absolutely no rust. No leak. The light has not come back on but fuel trim looks a little whacky on bank 2.
Bank one -1 to + 1. Bank two spending a lot of time -4 or so. No codes or pending codes. She poured a can of BGR 44 in for good
measure. Any ideas? She is suspecting my wife driving short trips back and forth to work may have carboned it up a little???
A -4 is still not that bad on a trim.
 
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