2004 GMC Sierra

CVLAVERY

MEMBER
2004 GMC SIERRA
V8
4WD
AUTOMATIC
111,000 MILES

Ever since we had some cold weather my 2004 gmc sierra 5.3L started idleing rough, it seems to run fine when i'm driving its just when i'm parked or stopped it seems like it wants to die. This doesnt happen all the time some times it will idle fine and the engine light will go out. The diagnostic engine codes are p0131, O2 sensor low volts. P0171, system to lean. P0300 Random/multiple cylinder misfire detect. I think it may be the fuel pressure regulator according to some of the other post i've read can some one give me an idea where the fuel pressure regulator it is located on this make and modle truck. Any other suggestions would be helpful thanks

Same issue is happening with my truck. Everything identical. Have changed O2, spark plugs, spark plug wires, cleaned MAF sensor.
Cleared codes today, same codes came back.
P0300, P0171, P0131
Lean condition bank1 sec 1, random misfires, O2 input voltage low
Did anyone ever figure out the problem with this. Was it the fuel pressure regulator. Where is it located

2 Replies

BRIAN 1

MECHANIC
1,030 POSTS

Before you do anything follow this info, Some customers may comment on a Malfunction Indicator Lamp (MIL) On or that the MIL is flashing. An actual engine misfire may or may not be felt along with an incorrect idle speed. Typically this occurs during cold winter months, on cold engine starts. Some vehicles may have been previously serviced for the same condition. Technicians may also find the following DTCs stored with the Tech 2 � P0131, P0133, P0134, P0137, P0138, P0140, P0151, P0153, P0154, P0157, P1133, which may be in conjunction with P0171, P0174, P0300 and P1138.

Cause
Water shock occurs when water droplets are present in the exhaust. The water in the exhaust contacts the sensor element inside the HO2 sensor, causing the HO2 sensor element to crack.

Correction
Upon diagnostic investigation, the technician may find that the HO2 sensor requires replacement. In addition to replacing the affected HO2 sensor, these vehicles should also be reflashed with the latest PCM calibration.
Post back with any other questions.