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Darn P0300 Error code

Discussion in 'Chevy Trucks' started by 2004chevy2500hd, Jan 12, 2011.

  1. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    Guys - Wondering if you can offer a bit of advice. Have a 2004 2500HD - Had plugs and wires changed (Napa parts) - general tune-up. O2 sensor replaced...all of the "normal" tune-up specifics. The multiple random misfire code disappeared - and then came back.

    Sequence of events:
    1) Purchased truck used
    2) Truck had check engine light on - had the following errors
    - O2 sensor
    - P0300
    3) Replaced plugs & wires / O2 sensor
    4) P0300 disappeared
    5) Two months passed - hauled 4200lbs of dog food (w/trailer) - just the other day...
    6) check engine light came back on
    7) had error code checked and saw that it was another P0300
    8) was plowing and all of a sudden noticed that check engine light was off (yay!!)
    9) confused - I searched this forum (chevy) and found this:
    http://www.plowsite.com/showthread.php?t=62238&highlight=p300
    ..from some time ago.....

    I went to the local autoparts store and picked up some SeaFoam to give it a whirl and wondered what the best plan of attack would be. Should I dump the whole thing into the gas? Or do the thirds thing that is recommended here - on their web site:

    http://www.seafoamsales.com/how-to-use-sea-foam-motor-treatment.html (check out video on right)

    Thank you
     
  2. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    also what brand of spark plug was installed ?

    todays newer stuff dosnt like diffrent brands/model plugs.

    i always install exact style/model factory plug. or you can get small skip/miss.
     
  3. leepotter

    leepotter Senior Member
    Messages: 122

    I've had nothing but problems with Bosch Platinums if that is what you used.
     
  4. mrv8outboard

    mrv8outboard Senior Member
    Messages: 197

    I use Seafoam in this way. I let the engine ingest it through a vacuum port or a small vacuum line into the intake. I use the whole can and it is like fogging out and engine, let it sit an hour or so, then run it off. Others bring up a great point about the plugs. Use what OEM replacements not a cross. Also you did get the premium wires from NAPA not the cheaper ones. You get what you pay for. You could also get some MAF sensor cleaner and clean your MAF sensor, be very careful when you do it as you can damage it.
     
  5. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    x1000 here as a mechanic for over 10+ years.

    unless its a german car motor. :dizzy:
     
  6. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    Funny you guys say that - I picked up and installed the Bosch Platinums - and then was told to switch them back to AC Delcos....Lost out on the money I spent on the Bosch had them in there all of one day - (call it - "paying for the experience" laughing ) - Plug wires are the OEM as well. -

    I'll try the vacuum line suggestion here in the next day or so

    Drove the truck around today - did some minor plowing and no check engine light...Oh well, I'm hoping that this is good news.

    I'll keep you guys posted and thanks again!!
     
  7. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    take the plugs back and tell them thay didnt work right. made the motor skip didnt work as advertised .

    but now YOU know what the correct way to do the tune up is . :salute:
     
  8. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    Excellent suggestion - I'll do that -

    Why didn't I think of that?
     
  9. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    daaaa :dizzy: :laughing:

    not in that mind set. you just want it to run right. :jester:
     
  10. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    lol - very true sir - very true - thanks again
    :nod:
     
  11. hummertech

    hummertech Junior Member
    Messages: 24

    what engine is in the truck?

    i would use ac delco plugs. most ac delco replacement plug are iridium now.

    the plastic intakes are known to leak.
     
  12. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    hummertech - I have the 6.0L in there. Great engine - not so great MPG

    :)

    Yeap - AC Delco's are in there now

    I still have to try the SeaForm - laughing - just need to find the time to do this.....
     
  13. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    04 2500hd. i be bettin since plugs its gas :dizzy: but if i recall o3 was last for 8.1L so he has 6.0 if i was a bettin man. :mechanic:
     
  14. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    smiling - SweetK30 - Want a challenge? Wanna help me replace this 6.0L with the 4cyl from my Accord?

    totally kidding.....

    80,000 miles and running strong
     
  15. stacks04

    stacks04 Senior Member
    from ct
    Messages: 119

    I would do a throttle body clean, clean the maf sensor, get some injector cleaner and watch were you buy fuel. It could be as liittle as some ****** fuel and causing intermittent skip.
     
  16. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    cuttin tourch and welder . not a problem. might not look good when done tho. :laughing:
     
  17. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    stacks04 - I have to try these after the SeaForm treatment - it looks OK for me - Keeping my fingers crossed :)
     
  18. herbert02

    herbert02 Member
    Messages: 70

    Did your check engine light come back on? Have the same exact truck and the same problem. Mine comes on when im on the highway. Did plugs, wires, upper intake gasket, mass air flow, sea foam, injector cleaner. Still no luck. Spent $500 at the dealer for them to just guess what the problem was. Ive given up on it.
     
  19. hummertech

    hummertech Junior Member
    Messages: 24

    6.0l should be coil near plug. do you have access to data? misfire history will tell you which cylinder is missing. kinda helpful to know which cylinder.

    they are know for cats clogging up also. will cause a misfire and burn exhaust valves if clogged for long periods of time.
     
  20. 2004chevy2500hd

    2004chevy2500hd Senior Member
    Messages: 123

    Guys - Thank you for the feedback. Good news is that my check engine light has not come back on (yet). Smiling - I bought the truck used (from a landscaper) and spent darn near $3000 on repairs - nothing major - but still not what I wanted to dump money on.

    Tires
    brakes (front and rear)
    rotos (rear)
    Parking break
    All fluids
    Tune-up (plugs and wires)
    fan clutch
    wheel bearings

    As for the data on the check-engine light - my next door neighbor in a SnapOn dealer who has access to those really nice computers that you can hook up to the truck - I'll have to get him to do that....

    I guess that it's not just me who has the check-engine light mystery