Having problems with your 2003 GMC Sierra 2500HD ?
I have a 2003 5.3 gmc sierre pickup multiple misfire code po 171 po 300 r. h. side clean l.h. side black. any answers
Fuel pressure regulator. Pull vac hose and see if it has fuel in it.
Repair Help & Product Troubleshooting for 2003 GMC Sierra 2500HD
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