Scan code P0171 for 1999 Lexus RX 300


Asked by Camry4ever Sep 24, 2013 at 10:09 PM about the 1999 Lexus RX 300 AWD

Question type: Maintenance & Repair

My wife drives the 1999 Lexus RX 300. The check engine light came on recently. We
diagnosed with code P0171 for too lean bank 1. We did clean the MAF sensor but the
problem is still there. We also smell too much gas. I believe it does burn all gas.
However, the engine run strong and smooth. No rough idle or crap. I don't know what
to do next. Any of your advices are very much appreciated.

6 Answers


spray wd 40 or carb.cleaner around the intake gasket or pour a little water while the engine is running. if it makes a difference in the way it's running you may have a vacumn leak. you can do this with all your vacumn hoses and connections also.

2 people found this helpful.

Thanks for response. I will do it to find out if there is vacuum leak. If so, I should fix the leak and it will take care the problem, right?


just starting with whats the easiest and a likely source of problem. hopefully you'll find a simple leak and it will stop your problem.


I pull o2 sensor off and see how much the convetor is clogged start it up and see if the sensor hole has a lot of pressure if clear it won't be coming out very much but if a lot is coming out the convetor is clogged also needs replacing fix right away if not the converter melts it does not take long,

3 people found this helpful.

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