2003 Chevy Silverado codes

2003 CHEVROLET SILVERADO
73,000 MILES • V8 • 4WD • AUTOMATIC
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JIMZUMO
  • MEMBER
  • 1 POST
i have 4 codes. p0171,p0174,p0300,p0430.
p0171: system to lean blank 1
p0174:system to lean blank 1
p0300: random/multiple cylinter misfire detected
p0430: catalst system efficincy below threshold blank2

i know nothing about cars .
what do i do or replace to fix all of this.
it all started when i put in a k&n filter
Jan 29, 2008 at 6:46 PM
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MASTERTECHTIM
  • ✓ASE Certified Mechanic
  • 4,750 POSTS
  • ASE Certified Mechanic
you have a few different problems. id first check the fuel filter and then check for a vacuum leak.
Jan 29, 2008 at 6:54 PM
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ASIRMANS
  • MEMBER
  • 3 POSTS
I have a 02 silverado and recently had my truck repaired. I had codes P0300, P0171 and P0174. Everyone was telling me it was my O2 sensors or vacuum leaks. With my truck, my intake manifold and throttle body gaskets were leaking and also my mass air flow sensor was out. This was causing the misfires which is code P0300. After they changed the gaskets and changed out the mass air flow sensor my truck runs great. Thankfully it was covered under warranty or it would have cost around $700. The tech said it was common on our year models.

Do you have an aftermarket air filter like a K&N?
Jan 30, 2008 at 7:12 PM
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