i have replaced everything but the engine and computer and still cant get my k&n intake to run without getting a cel. 0171. gs 400 any thoughts???

 

Have the same issue, spent a few hours with my mechanic diagnosing it and we have come to the conclusion that the bank 1 o2 Sensor is on its way out, has a slower response when compared to the other sensors and thus why you keep popping a bank 1 lean code. I will be changing mine next week and will update you if you want. Have similar setup, GS400 with K&N. But I was intermittently getting the same code with stock intake as well.

 

^ Agreed. Swap out your O2 sensor(s) and you'll be good to go!

 

as i stated in the above, I HAVE CHANGED EVERYTHING. o2 sensors-all of them, mas air flow sens., cleaned throttle body, removed and cleaned the injectors and fuel rail, replaced fuel pump,
spark plugs- the correct expensive ones. i too was getting the short reading on the bank 1 side o2 but made no difference.. 0171 is lean bank 1. if i put the stock intake back on, it all goes away . . any other ideas.

 

let me know how it works out for you.

 

I will. However with all of the work that you have done I doubt that it is the same issue. But what I would do is grab a good obd2 scanner that will allow you to have real time access to sensor values, compare what happens with stock intake and then compare what happens with the K&N. Make sure that you have someone else looking at it because someone needs to drive.

 

If you changed everything out and there are no faulty new parts then I GUARRANTEE you have a vacuum leak! I would check all vacuum lines AND the PVC valve. I noticed on mine one day when I was getting the PO171 that the PVC valve (vacuum line attached) was actually not fully seated in the hole going into the engine (intake manifold). I corrected this, re-set my ECU and it never came back on again!

 

good ideas. i did drive with the scanner connected but never with the stock intake to compare. that million dollar snap-on unit. any good ways to test for vacuum leaks besides the old carb spray trick? i did that with no results. maybe i didn't do a thorough enough job. local lexus shop said that toyota runs their injectors near their max flow limits and with the intake it just cant compensate enough. bigger injectors was their answer, but it sounds like a guess to me.

 

Idk bro,
been runnin' my K&N set up for almost a year now with no issues at all..
all I got for now is the k&N w/ RMM cat back..

 

Just put back my K/N on Sunday and everything works fine. Had it on for about a year. Took it off last spring. Just put it back on. Always worked great.

After a while I get tired of the wheezing intake. It only roars on heavy throttle, otherwise it's a bit of a torque hog so I take it off. Then I get the itch for the roar so I put it back on.

Make sure you got all the hoses are tight and on the right connectors. Also make sure the air flow sensor is on right with no leaks. I also give it a good clean using CRC sensor cleaner. At the same time I give the throttle plate a good cleaning using a carburater cleaner spray can.

 

try spraying all the lines with soap and water you should see bubbles if its leaking

 

Very stupid suggestion but...is your MAF sensor installed in the correct direction? lol The opening part of the MAF sensor should be pointing towards the intake filter side.

 

a vacuum leak wont make bubbles. sorry.

 

checked that. even replaced it with a new one.

 

i think maybe there is a leak when vacuum is high???? e.g. wide open throttle from a stop, but this is hard to test...Anyone wanna ride in the engine compartment while i do a quick run? just kidding.... I cant believe i feel like i have to say that.