im getting the codes p0172 and p0175 and the CEL no traction and check VSC. first i cleaned the maf sensor then changed my maf sensor with one that claimed to be a Denso I bought online and the codes would come back instantly even after resetting the ECU. Then one day I let my brother borrow the car and he decided to drive it like he stole it or a dam NASCAR and I got a one time only code thats never came back after I reset the ECU that said random misfire. Then I bought a new maf sensor from AutoZone and the codes and CEL and all the bad lights disappeared so I was super super excited and thought I solved my problem but then a few days later I started getting the codes p0172 and p0175 again and then the CEL and all the others came back again. Every time ive changed or cleaned maf sensor I reset ECU by unplugging the battery for about an hour and pumping the breaks making sure all the power is out and all that good stuff.... Am i suppose to let the car idle for 10 minutes after changing the maf sensor for it to learn the ratio or do any other tricks after changing the maf sensor because I never did any of that and im still getting codes for running to rich in bank 1 and 2..... The dealership tried to tell me that they think its an o2 sensor but could both sensors go out at the exact same time? I know its best that when u change one sensor to change them both.... Ok so for the first few months of having this problem the car had absolutely no performance issues it ran like a champ even after I cleaned and then changed the maf sensor untill my brother raced it around for a day and a half, But now if I start it up when its cold I have to hold the gas a little untill its fully warmed up or it'll die, also even after its warmed up when I hit the gas it wants to hesitate a little Then jerk forward sometimes not Every time tho more so when its cold.
O ya and btw I have an ETI electricaly tuned intake big shiny pipe with maf sensor towards the filter and its an oiled k&n filter that's clean. so the first dealership I took it to tried to tell me that the module that comes with the intake that's suppose to tell the ECU what fuel to air ratio was no longer working and told me to unplug it and.plug the maf sensor directly into the wiring harness and I did that and when I did then I got the codes for it running to lean in bank 1 and 2 so i plugged the module back in thinking it was working right and thinking that its better to be running rich then lean. This is every thing I can think of at the moment if I remember anything else ill definitly post it and update this.... Ive posted on this problem in the past maybe a few months ago but theres been quite alot of things changed since then a few big things like now I'm having performace issues with it stalling and hesitating.... Im hoping with all this info someone out there can please tell me what's wrong because I just don't believe the dealership saying both o2 sensors went out at the exact same time and those are an expensive items to buy when they are just guessing and they may be perfectly fine.... They told me if that doesnt fix the problem then maybe its my ECM and I dont wanna hear that b.s. guessing stuff from the dealer that they wanna charge crazy amounts of $ for and still cant gaurntee that it'll be fixed.

 

Yes I've seen your post about this, and conmented.

​​​​​My guess is eBay maf is junk, AutoZone is junk too. Best bet is get one from RockAuto.com DENSO.

Second is I really think it's the AEM intake the diameter pipe is too large it's a 3.5" diameter. It's loosing intake velocity big-time. For it to run correctly you'll need a proper tune. Look at rr racing they have a tuned intake. God knows how AEM is tricking the maf with resistors and what not. I've tried a larger intake pipe withy is250. Trust me they make my car run like cow poop. As soon I put the stock back on it runs like a champ.

They only way is to know what is really going on is it's going to have to be checked out with tech stream, or equivalent. They need to see what the sensors are reading. MAF, 02's etc etc. So did you pay Lexus to run disgnodiacs?

https://www.google.com/amp/s/www.my....40601/%3famp=1

 

I found a bunch of links on the AEM ETI.

https://www.scionlife.com/forums/sci...recall-215021/

https://www.scionlife.com/forums/sci...roblem-217337/

 

I believe I had the same codes a month back. The print out I got said to fix it was 1 of 5 things.

-clean MAF
-replace MAF
-replace O2 sensor
-clean throttle body
-replace throttle body

I cleaned the throttle body and cleaned the MAF and was able to fix the issue. I watched a couple YouTube videos and bought the cleaner from an auto store.

Hope this helps.

 

^^ Agree 100%. And thank you for those carriage returns. So much easier to read!

I would ditch the intake completely. Bling is only cool if it works. In this case it it very likely the source of the problem coupled with none OEM MAF sensors. Besides, there is no way an otherwise stock 250 needs a 3.5" blow hole. You want velocity and that is killing it.

 

Its a is350 and ive got a stock maf sensor and cleaned throttle body but no I haven't taken it to dealsrship yet or played some some to tune it. Cleaning ma f and throttle body fixed last time but ill codes came back and its guzzling gas and has 8s extremely expensive r8fht now

 

Because it's the O2 sensor like the Dealer told you, and/or the Cats. They will come and go. Then one day they will stay on. I think that day has come. Both sensor at the same time. Ahhh both have sensed with the same mileage, gas, dirt contaminates, on so on. One engine same conditions yes its 100% possible. Especially if one want you did not replace, 2nd went right behind it. When your Bother drove the crap out of it, it blew the stoppage or O2 problem out temp.

I would also make sure you have a quality MAF also. This is also throwing you off possibly too? Multiple things wrong, need all fixed. I maybe wrong, but last I looked good O2 sensors a while back and they are are Not that expensive at all. See if you can find the O2 extenders that defeat the readings to test and see.

Which AEM do you have? The Pipe with the Stock Air Box? Or a Pipe with Cone filter Stock Air Box gone?
Do you still have the original MAF?
How many miles and what year? I have a feeling I know how high the miles are.