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Hi All, Excuse my English I have Lexus LS430 2005 model and it has 76130 miles. Recently it started to throw two error codes P0171 [corrected--Ed.] and P0174 , they are related to Air/Fuel Mixture System Lean so i cleaned all Oxygen sensors and MAF using Electronic cleaner and replaced two cracked hoses but it made no difference. I am using techstream software to get all parameters of the car but of course can't understand them but it shows a high long term fuel trim 34% as i read it should be much lower than this. Please help !!

Comments (11)
No. 1-5
Ward Sy
Ward Sy

As a conclusion, for any one having P0174 and P0171 codes there are many things might cause these codes in my situation it wasn't MAF or O2 sensors or a vacuum leak but they could be for another case. For me one of the followings resolved the issue but idk to be honest: *Replaced all spark plugs *Injectors cleaning and replacing their seals *Replaced fuel filter located in back seat *Throttle and Catalytic Converter cleaning After that i reset codes and didn't come back till now and hopefully the issue is resolved

Please help me with the below parameters immediately after doing all the above if anyone understands these values

Techsus
Techsus

Do this then: How to Find Vacuum Leaks With a Cigar (Life Hack)

Techsus
Techsus

You said two error Codes but ''P0174 and P0174'' are the same.

dil 89
dil 89

You have a big vacuum leak probably the brake booster

dirty dan
dirty dan

Try using a smoke machine to check for leaks