2003 chevy silverado Z71 5.3

**EARZZ** · 01-10-2010 01:57 PM

guys im new on here and just bought a truck from a shady dealership.the day after i bought my check engine light came on and i had my codes read.i had 10 codes show up but 4 of them were repeats.the 6 codes were (1)mass air flowsensor(2)heated oxygen sensor bank 1 sensor 1(3)same as #2 but bank 1 sensor 2 (4)same as 2 and 3 but bank 2 sensor 2(5)cylinder misfire random cylinders (6) knock sensor condition. i am not a very mechanically savvy person but i dont really want to go to a shop to get it fixed bc they r way too pricey around northwest arkansas where i live. any help would be greatly appricated.

**Bowtie boy** · 01-10-2010 02:12 PM

If it were mine man I would take it back.

**RedHeartbeat** · 01-10-2010 02:12 PM

Start out by testing all the fuses, check there is 12v through both sides of them using a test light or multimeter. You will have to turn the key on for some of the fuses to be powered. Follow that by checking the engine grounds at the back of the engine block on the driver's side head. Also check the Ground on top of the engine block in the center between the cylinder head. One of the grounds could be loose or broken. You can also check the ground wire path from the sensors in question by using a multimeter between the black wires to ground.

**Toadz** · 01-11-2010 02:42 PM

Bring it back...why did you buy a truck from a shady dealership?

**EARZZ** · 01-11-2010 06:55 PM

well i didnt realize it was a shady dealership until i tried to take it back and they told me that they dont take them back.i am going to change out the plugs and wires and the o2 sensor for starters. then go from there i guess.