03 silverado 5.3 P0174 *solved*

[mlkmgr]

Have a 2003 Silverado LS with 5.3 @ 149K miles. Engine running sluggish and flashes check engine light once you try to accelerate above 50mph. Pulled codes. P0174 and P0300 r codes. Changed plugs, wires, and fuel filter. No change. Plugs on passenger bank all black and sooty (see image). Drivers side showed sm wear but nothing like bank 2. Fuel is 48psi idling and bumps to 53psi when revving. Fuel pressure regulator is not leaking and shows no sign of wetness anywhere in hose connected. 

 

Reading all over web about possibilities from fuel pump to upper intake gasket to EGR to MAF. But those are all usually accompanied with P0171 also. 

 

Any thoughts?? 

Edited September 25, 2018 by mlkmgr
Solved

[sefiroxx]

O2 sensor failing. Causing system on that side to run rich. Carbon buildup may be causing misfire.

[mlkmgr]

Any way to be certain? Guy has limited funding to fix this and he cant afford to throw money at parts. Thanks for the reply!

[sefiroxx]

Better scanner/code reader will provide data stream showing what the o2 sensors are sending

[mlkmgr]

My scanner shows short n long term fuel trims. Just not sure what to look for or how to interpret reading. Would this b what i am after? 

[sefiroxx]

Of positive, the extra fuel is being added, negative them fuel is being removed.

High negative fuel trim;
- MAF sensor problems
- high fuel pressure
- leaking fuel pressure regulator diaphragm
- faulty evaporative emissions components
- leaking injectors
- defective O2 sensors
- exhaust leaks/pinholes before the O2 sensor
- coolant temp sensor problems
- low compression
- incorrect camshaft timing.

High positive fuel corrections:
- MAF and O2 sensor faults
- vacuum leaks from intake gaskets/hoses
- unmetered air (intake snorkel leak)
- clogged or dirty fuel injectors
- fuel delivery issues
- exhaust restrictions

Since your problems are on one side, and apparently affecting all cylinders, only components that are dedicated to one side are in consideration - the O2 sensors, (then the wire harness to the injectors)

[mlkmgr]

Sorry I typed the wrong number which I know changes everything.......the code i

 

P0174!! Fuel Trim System Lean Bank 2

 

[mlkmgr]

Just to close this out...code was P0174 only with the occassional flashing engine light (P0300) when i accelerated hard. Changed plugs, plug wires, fuel filter, cleaned MAF, and the upstream O2 sensor on passenger side. See the pic but this thing was caked in black soot also. Idk when the last time any of the O2 sensors were changed but this definitely was bad. Going to order the remaining 3 and swap em out to be safe. Can accelerate without issues, no engine shake, and all is good again. 

 

Edited September 25, 2018 by mlkmgr