Well, it is hard to say what "the hose on the left" is unless you can tell me where it goes to and from.

I can tell you that vacuum leaks will mess with your oxygen sensors. Also, if the "hose on the left" is the air intake hose that connects between the air cleaner and the throttle body, that will mess with your Mass Air Flow (MAF) sensor and totally mess up your air/fuel ratio. If there are any vacuum leaks or air intake leaks between the air cleaner and the throttle body, those should be fixed before anything else.

With all that said, I have had LOTS of problem with using aftermarket O2 sensors on Lexus vehicles. If you have all of your vacuum and air intake leaks fixed and the problem persists, I would recommend getting new O2 sensors from the dealer (if the ones you installed are aftermarket).

I understood that the O2 sensors were "new". The problem is that NEW and GOOD do not mean the same thing. If they did, there would be no use in the English language for the word "Warranty". If I had a dollar for every defective part that I have seen come straight out of the box during my 37 year career, I could retire very comfortably and send you a few thousand.

I do not mean to be rude, but if you do not know what an air cleaner or a throttle body is, I really don't think you should be messing around in your engine compartment. You might want to dig your owner's manual out of the glove box and blow the dust off of it and get more familiar with what is what under the hood before trying to fix the car yourself.

I am not saying this a put-down or anything....Please do not take it that way. It is just that you may end up costing yourself a lot more money by trying to do things yourself than it would cost to get a professional to look at it for you.

A good mechanic can take one look under your hood and make the determination if a vacuum leak or an air intake leak could be the cause of your problem, and he probably would not even charge you anything to do that.

I am telling you this for the same reasons that my brother (heating and air-conditioning specialist) tells me not to mess with my furnace....I could get hurt, or make the thing worse, because I do not know how it works.

If you are in need of further information, please let me know how I can help you. If you would like to speak to another expert, I can opt out and open the question so someone else can answer your question.

Otherwise, it has been a pleasure serving you and I hope to work with you in the future sometime.

Please do not forget to rate my service. Also please remember that a rating of 1 or 2 is considered a NEGATIVE rating. If you feel that the service I have provided does not deserve a better rating than that, please reply and let me know what I can do to serve you better. My goal is to make sure you are completely satisfied and feel that you have received good value for your money.

Thank you,

-Autotech58