Quick diagnostic emissions question

Discussion in 'The BS Topic' started by 327 BlackBird, Jan 22, 2011.

  1. MrAzzhat2U

    MrAzzhat2U Veteran Member Lifetime Gold Member

    Jan 31, 2000
    Lewes DE
    What he said!!The misfire will give you the HO2 codes as Dave said.The misfire is what needs to be fixed!
  2. 327 BlackBird

    327 BlackBird Veteran Member

    Um, I know they are NGk premium blue wires. I can't remember the exact name. The old wires are in the garbage as they were brittle. Looks like the previous owner changed plugs only.

    I have seafoamed the truck already. Through the intake and fuel tank. I have a feeling it may be the plugs. Everything else works fine no vacuum leaks to speak of. No other sensors acting up.
  3. 327 BlackBird

    327 BlackBird Veteran Member

    I agree. I know a misfire will throw out 02 codes. On the other hand a 02 that's not switching correctly can sometimes cause a misfire as well, but not very likely but it can happen. Good ideas. Keep them coming. I am gonna brave the -20c weather and head outside soon to change out the plugs.
  4. Cardinal

    Cardinal Veteran Member Lifetime Gold Member

    Jun 22, 2003
    Endicott, NY
    +1 on new plug wires. JD (youngest son) took AC Delco certified courses at SUNY Morrisville so he can tell me what to do with the 2000 Tahoe when it has problems or I service it.

    JD was emphatic that we use AC Delco spark plugs and replace the spark plug wires when I did a "tuneup" on the Tahoe. He gave the same reasons that were given to here plus: 1) the wires are OLD, time to replace them (Tahoe had 100K on it at the time), 2) the possibilty of removing the spark plug wire without damaging it is 0%, 3) it is good insurance to change them rather than gamble on them being OK to use (see #2).

    +1 for STOP driving it till the problem is fixed or you'll be replacing the cats = HUNDREDS of dollars to replace.

    As for fuel injector cleaners, I personally like the Lucas fuel injector cleaner. I had a winter beater Corsica that had a misfire. At the time I had a part time job at Advance Auto (had to quit because Evil had a chokeing incident while I was at work. She had to do the Hymlick manuever by herself over the back of a chair! Part of her auto immune disease is she has NO swollow reflex). Anyway, one of the guys at AA said to put the Lucas in a full tank of gas run it on the highway (which there is one 2 mile stretch of four lane on the way home). As God is my witness, by the time I got to the end of that 2 mile stretch, the "misfire" was gone for good! BUT, do not run the injector cleaner till you get that misfire fixed or it could ruin your cats for good.
  5. 327 BlackBird

    327 BlackBird Veteran Member

    If the misfire is still present after the tuneup I will run to local GM stealer and grab some ac delco wires. I should also pick up a fuel filter. I doubt it's been done in a very long time.
  6. 327 BlackBird

    327 BlackBird Veteran Member

    Well I think I found the culprit. Seems that a "premium" plug wire was not staying on at all. It would click and back off.

    Not saying that this is the problem for sure. But it makes most sense. I reinstalled 6 of 8 of my ac delcos. Gonna pick up the remaining 2 today and some injector cleaner and throttle body cleaner. And some new ac delco wires.

    The truck runs better. Idles smoother. Won't know how much better till I take Tanya out for dinner in a few hours.

    Check out the before video I took. Look at all the carbon flying out of the tailpipe!!! Nice and clean now nothing is blowing out.

  7. Knuckle Dragger

    Knuckle Dragger Administrator Staff Member Lifetime Gold Member

    Nov 2, 2002
    Waddell AZ
    The o2 is so low on the priority chain anymore it's highly unlikely the o2 will cause a drivability concern. The new systems are fair better equipped to deal with false data then they were 15-20 years ago.

    I"d guess by the picture you found the issue.
  8. MrAzzhat2U

    MrAzzhat2U Veteran Member Lifetime Gold Member

    Jan 31, 2000
    Lewes DE
    Bingo! We have a winner!!!!!

    If you have access to BG products I would use 44K in the fuel tank.
    BTW,don't spray TBI cleaner directly on the Throttle body,spray on a rag and wipe the plate with it!
  9. SpeedAddict02

    SpeedAddict02 Veteran Member Lifetime Gold Member

    Dec 31, 2002
    Wallkill, N.Y.
    holy crap. That spark plug gap reminds me of an old girlfriend!!

    lol j/k
  10. Mike N

    Mike N Administrator Staff Member Lifetime Gold Member

    Jan 13, 2002
    Spencerport, NY.
    All the carbon on the plug in your pic makes me think it was loose and not sealing to the head correctly, or you have an exhaust leak blowing crap all over the plug. Neither situation is ideal, imo.

    Stupid question, but are the oe Delco plugs a taper or washer seat style? Could be the replacement plugs are the wrong ones and that could have been giving you the problems you had.

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