skip , hop , and wobble gremlin,, got me puzzled..................

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by redchev4x4, Aug 9, 2013.

  1. redchev4x4

    redchev4x4 Member

    my original post must not have went through,, but he goes.........

    2003 4x4 4.8 engine auto tranny,,, 175,000 miles,,, every so often with no pattern it start missing and skipping and when you
    slow down or stop sometimes it will go dead. this is an ongoing thing for about 4 months now.. sometimes it will go 3 or 4 weeks
    between this happening. no check engine light ,, no warning,, the onlt constant is it has to be warm or hot.. and it takes 10 to
    20 miles before it ever happens. plugs and wires have about 90,000 on them,, this will be my first replacement,,, but its really
    weird. you guys got any ideas of other things to look into? i have replaced the fuel filter,, and cleaned the air filter,, someone said
    that the MAF might be dirty,,, don't know bout that but possible...

    what ya'll think?
    red truck 1.JPG

    terry m
  2. j cat

    j cat Epic Member 5+ Years 1000 Posts

    well with missing I would expect p0300. anyway just get a fuel pressure gauge and start making pressure checks. if the pump is shot replace the pump relay and regulator that way this will be all done and no other issues.

    on spark plug wires measure the wire resistance they should be around 600 ohms. if this is correct your good. now if you buy new wires measure the resistance if you find the new wires are with higher resistance then bring them back they are not for your vehicle. you see low resistance wires that are the correct part cost more to manufacture. many sell these cheap wires of the wrong resistance and this messes up PCM ignition control.
  3. redchev4x4

    redchev4x4 Member

    i priced the ac/delco wires and plugs,,, wires were about 70.00 and plugs were 5.20 each..
    i would think the ac/delco wires would be the correct resistance.
    i got my doubts about it being the pump because it has great pressure at the engine,, and it runs like a new one until this glitch hits it. i think something electrical is breaking down with heat... yesterday it did for the first time in weeks , i drove it about 35 or 40 miles,, (which is about twice as far as drive to work every day)
    after about 40 miles it just started out on the highway skipping and missing. the last time it did it i put code reader on it but it said all was good no codes to read. so i don't know.... this is looking like a hunt and peck thing now.
    but thanks for wire info i will have to check into that before dumping 70 bucks in a set of wires.

    terry m
  4. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    Could be the fuel pressure last truck was doing that also,replaced it and it was fixed
  5. j cat

    j cat Epic Member 5+ Years 1000 Posts

    even if you get the ac delco wires you must check for the correct resistance . sometimes these wires are defective !

    just got down to autozone and do the fuel pressure check. they should be able to help you .

    if the pump is shot get ac delco or delphi pump. do not buy airtex even if they give it to you for free.
  6. redchev4x4

    redchev4x4 Member

    ok will do,,, i didn't know they could do a pressure check on the pump.
    kinda makes you leary about leaving the house with,,, it always straightens itself
    out after it cools for just 5 or 10 minutes,, so i don't know....................

    well out to pull headlights out of the wifes equinox to do a headlight restoration on them with the 3M kit,,, fun fun fun!!!!

    terry m
  7. RAV52202

    RAV52202 Rockstar 100 Posts

    We have a truck at work that will over heat the fuel pump relay and the truck will die. in the winter that is fine cause we pull it out and throw it in a snow bank for a minute. Just a thought. we still havent figured out what is making it do that yet. sounds similar only cause if you let it sit or change the fuel pump relay it will start right back up and it will do it when it feels like it.
  8. j cat

    j cat Epic Member 5+ Years 1000 Posts

    if the fuel pump relay over heats then you have a short circuit/power cable leakage. I would measure the fuel pump current. also check that the correct fuse is used. this may cause a fire.
  9. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Relays will also overheat if the contacts are burned/corroded. The resistance of the corrosion at the contact point will cause a voltage drop and heat will form.

    The description of the intermittent problem does sound like a fuel shut off. If the pump is good, I would change the relay. The last time I bought one, it was around $10
  10. redchev4x4

    redchev4x4 Member

    i will try the relay,, its cheap and could be it,, i am willing to try anything now, ask autozone if they could check fuel pressure,, they said no but we can rent you a tool to do it for 150.00 . then return your money when your done with it. yesterday i got a new standard air filter ,, some throttle body cleaner and some MAF cleaner,, this will be my next steps. i am leary about taking it on the interstate to much now.... seems like its worse when i run interstate sppeds for any length of time,,or it seems to bring on more often.

    thanks for the tips and ideas

    terry m

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