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2003 silverado check engine light

Discussion in 'GM Powertrain' started by txsilverado, Dec 27, 2009.

  1. txsilverado

    txsilverado Member

    I have a 2003 silverado with the 4.8l gas engine. A couple of weeks ago the check engine light came on so i used a code reader and it was saying the truck was running too lean. I assumed it was bad gas, once i ran it out though, the problem continued. Now i have read it again and its saying there is a problem with the mass airflow sensor performance, running too lean on bank 1 and 2, and multiple random cylinder misfires. The only syptoms i have noticed is erratic idle. It will go down to 200 or so then back up to 6. So far i have replaced plugs, wires, fuel filter, and mass airflow sensor. Any help with what the problem is would be much appreciated.
  2. chew246214

    chew246214 Rockstar 100 Posts

    if it's po420 the code was told cats are bad, and at the same time the lean code bank 1 or something like that maybe fuel pump losing pressure... thats all I can help you with... I'm chasing a check engine light that keeps changing codes and these are the 2 most frequent.....
  3. txsilverado

    txsilverado Member

    Alright thanks. plan to have it checked out tomorrow so ill update details

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