p0171, p0174 on 2013 silverado 4.3L

Question

change air intake,all fuel injectors,all 02 sensors,MAF sensor, DTC light still came on the next day

Answer 1

P0174 and P0171 are lean code condition, right at the PCVC valve that elbow hose tends either rip or collapse, so it a good area to check, also at the brake master cylinder if you have the vacuum assist, that area where the master cylinder seats at the booster you should check that area, you can use brake cleaner to spray along that area to note any change in RPM, to find the vacuum leak. This type of engine due to the fuel strategy tends to build up carbon on the intake valve as it gets worse it develops a misfire condition, bad enough the intake manifold has to be removed just to get the carbon build up out, Use a fuel injector cleaner that you add into the fuel tank.

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