bigrobbyt

Seems like there has been a few people out there with this problem. Check engine light - code P0171 came up, car is idling rough, hesitating etc... I've cleared the code and it will sometimes run fine for the day but then come back the next day. I took out the MAF and cleaned it well, definitely seemed to help with response, but 30 miles later is started hesitating and the CEL came on again.

Whats my next course of action? I've talked to a few mechanics and they said if I gave the car to them they would 'guess' and replace an O2 sensor. Well there is 3 of them, all over $100 a piece what if they're wrong?

I have a car scanner, one that can read while you are driving, but I don't know what specs the MAF should be at, is 3.5 lbs normal for 30 m.p.h.?

Please let me know any thoughts. Any help is appreciated.

IndyRX300

Try cleaning your TB and ICV . That helped tremendously on mine.

salimshah

see https://www.clublexus.com/forums/rx-...141-p0330.html

Cleaning IACV and TB may not be enough.

Salim

IndyRX300

True, I was just steering him towards the most cost effiicient way. Unless he is only getting 6mpg like the owner in the other post. That would be a nightmare.

bigrobbyt

Thanks for the help guys. I'm not sure cleaning the TB etc would work only because it was a sudden thing. Few days ago it was running fine, all of a sudden just started running like crap. That tells me something like a sensor or whatever broke, not a buildup of gunk over time. But I'm the one here asking advice, so maybe my thinking is wrong.

Lexmex

Run some fuel injector cleaner through it, too. Air/Fuel has two elements. If the fuel injectors are clogged, that can throw the ratio off.

IndyRX300

@ Lex, Since the tips of my old plugs were all white. Do you think that I would benefit from running some fuel treatment thru the car now? Or is there a possibility of harming the new plugs?

Lexmex

Cleaner can only help here. There may be some temporary hesitation when it is cleaning the injectors out, but that should dissipate quickly. Again, that was only when my injectors got really clogged south of the border.

IndyRX300

Thank you sir

bigrobbyt

update - I replaced the MAF sensor, but after 50 miles the CEL came back on, now instead of reading code 0171 it is reading 0136, bank 1 sensor 2, replaced that sensor (nice DIY writeup in the sticky section, though I was able to shortcut it and not take out the drivers seat) The time I saved not taking out the seat did not make up by any means the time I lost when I went to remove the old sensor, it was so rusted 1 bolt head was already missing/rusted off and the other took about a quarter of one turn and snapped off. Had to grind it all smooth, drill and tap new bolt holes, ugg. Still need to drive the 50 miles to see if I get any more codes, but at least now it is back to running smooth again.

AngNKY

What does "TB and ICV" mean from post #2?

RX300CE

TB= Throttle body
ICV = Idle Control Valve