98 suburban-check engine rough idle-sudden

Discussion in 'GM' started by phoebeisis, Oct 26, 2015.

  1. 08EscapeHybrid

    08EscapeHybrid Moderator

    I get my plugs and wires done in just over an hour... I do it from the top. Not that hard, but I'm tall, and you mentioned you're short. I use the Mobil1 0W30 in mine. You get the higher grade true synthetic. The book calls for 5W30. I don't even use 10W oils in my vehicles that call for 10W. I use 5W30 "Extended Protection" in the 1981 Regal.

    With Mobil1 the Zero weight oils, and the grades marked "Extended Protection" are true synthetics.
     
  2. phoebeisis

    phoebeisis Well-Known Member

    Redy
    Once the weather improves
    I wil check the #1 wire-all the wires-as I replace them
    my plug wires are arriving today
    but the cap rotor-are still 3 days away.
    You hope it is something easy-
    IMAGINE how much I hope it isn't those injectors-10-20 hours of pulling stuff off-putting stuff back on-
    And another $350-on top of the $100 for wires cap rotor

    Escape-Yes 5'5"
    I have a step I hang on the tire-works pretty well for above work

    Ahhh-I remember when Mobil 1 went from being a TRUE FULL SYNTHETIC
    To some sort of cheaper "Legally synthetic-but not really synthetic"
    There was some lawsuit at the time-maybe involving castrol's synthetic ??

    So the 0w30 is a TRUE FULL SYNTHETIC
    I switched to the 10w30-from 5w30 mobil 1 because my oil pressure was 17 psi at idle
    plenty high- enough but NOLA is HOT-

    I do use the Extended service-mobil 1 10w30- FULL SYNTHETIC?
    So I am actually using a full synthetic?- didn't know that-guess it explains the $5 more per 5 qts.


    the 0W30 is also a TRUE full synthetic?? Maybe I will give it a try-in the Prius first
    I use 5w30 extended service in it now($29 5 qts walmart)

    Thanks for the help
    Charlie

    PS Saints won-giants stunk worse
     
  3. 08EscapeHybrid

    08EscapeHybrid Moderator

    So the 0w30 is a TRUE FULL SYNTHETIC
    I switched to the 10w30-from 5w30 mobil 1 because my oil pressure was 17 psi at idle
    plenty high- enough but NOLA is HOT-

    I do use the Extended service-mobil 1 10w30- FULL SYNTHETIC?
    So I am actually using a full synthetic?- didn't know that-guess it explains the $5 more per 5 qts.


    the 0W30 is also a TRUE full synthetic?? Maybe I will give it a try-in the Prius first
    I use 5w30 extended service in it now($29 5 qts walmart)

    Thanks for the help
    Charlie

    PS Saints won-giants stunk worse[/QUOTE]


    Not sure about the lawsuit, but yes. Zero weight oils and Extended Protection oils are true synthetics. I would not worry about heat. The oils are true synthetics and can take it. I use the 0W30 in my 98 K1500. I'm just shy of 200,000 miles. I've been using Mobil1 in it since I bought it with 109,000 miles. Runs smooth and quiet, and only uses 1 quart oil / 5,000 miles.
     
  4. phoebeisis

    phoebeisis Well-Known Member

    08 ESCAPE

    The prius will get the 0w30 this -dec-oil change
    Since I already bought the 5w30 extended-5 qts-the suburban will get that instead of the 10w30 extended performance-
    lazy man's oil-once a year changes-perfect for me

    Thanks all-this weekend-I should have all the electrical stuff-
    so I'll keep you guys posted-
    I'm pessimistic- thinking it might be the injectors-but maybe I will get lucky
    Charlie
     
  5. phoebeisis

    phoebeisis Well-Known Member

    UPDATE- started today-cool 59 degrees-seemed to run a bit better with cooler air
    If that is so-it might be an indication that it is a bad-leaky-injector
    NOT a happy thing-since that means my ignition parts replacement-won't help much
    and the injectors-are a $400 15 hour back neck ache inducing DIY project
    and no way will I farm it out
    I work cheap-and I had a bad experience last time I farmed out to a shade tree mechanic(my fault for being lazy and cheap)

    Crummy weather-constant heavy rain last 2 days
    But today cool-59 degrees -we-NOLA suburb-consider 59 degrees overcast and high humidity
    to be COLD
    Anyway no work done
    If rain holds off-I will do cap wires rotor
    post an update-but running better in cooler weather-
    not so good from a "what is causing it" point of view
     
  6. phoebeisis

    phoebeisis Well-Known Member

    It was the dist. cap
    Changed it and the rotor
    and now it runs perfectly
    The 8 aluminum looking studs contacts were covered with grungy greenish corrosion-
    must be some copper there the aluminum alloy or maybe in the metal contact of the rotor
    There was dusty green "stuff" on the edges of the cap also
    Didn't bother with the wires or plugs-
    1,5 hours bending into engine bay was enough for me
    and th wires-trickier to follow than you would think-
    Have to literally follow by hand

    Redy suggested- 10-26-15 than the onset on a rainy day could indicated a bad cap
    funny-once dry-it was still bad-but it sure became OBVIOUS on a heavy driving rain day
    Thanks all-I am very relieved it isn't the injectors-
    $400 and 15-20 back breaking hours avoided
    Oh-pretty sure my intake gaskets are leaking to the outside AGAIN-not much-but I see what is in my future


    Redy below-10-26-2015
    A vacuum leak (including a stuck-open PCV valve) should be a lot less obvious under load than at idle.

    Your "heavy rain" might be a significant clue, if it has revealed a fault in the ignition system, for example a bad distributor cap, which tends to show up in wet conditions---assuming it has a conventional distributor.
     
  7. RedylC94

    RedylC94 Well-Known Member

    Aha, and you're welcome! Your original description looked like classic symptoms of a bad cap. Can you see a hairline crack or arc track on its interior surface?

    Some wise person---I forget who---once said something to the effect that if you hear hoofbeats, watch for horses before you go looking for zebras.

    Take a break!
     
  8. phoebeisis

    phoebeisis Well-Known Member

    I lucked out
    It seemed to be pretty abrupt onset-
    and the yellow flashing light and codes-were abrupt obviously-and they showed up exactly when it started missing-raining hard on way to school.

    No matter what I think the probability of the part being the cause of the problem
    I always do the "cheapest/easiest" first
    The $3 PVC- and 3 seconds done 1st
    then the $43.50 delivered cap/rotor(1.5 hours)-
    Frankly I couldn't see any obvious crack or track-
    but plenty of sorta strange greenish powder dusted on the inside of the cap
    Copper-ish corrosion-BLASTED off the contacts-which look like some aluminum alloy-
    can't imagine that is normal
    The cap contacts-all 8 of them are corroded-greenish-almost foamy looking (but metal hard) corrosion.

    The rotor contact looks Ok-

    Yeah I am very happy it isn't the injectors-
    I have a "tire step" that lets me lean waaaay in to the bay
    but bent at waist-leaning on the fan shroud-or something"sorta solid" looking-
    hard on my 64.75 yo back

    Thanks all
    Charlie
     
  9. 08EscapeHybrid

    08EscapeHybrid Moderator

    Glad you got it fixed on the cheap!
     
  10. phoebeisis

    phoebeisis Well-Known Member

    08
    Right-
    cheap is good
    and LUCKY- which I was-good too
    The cap rotor-ACDELCO- ebay-were $43.30 delivered
    Didn't install the wires-they were $49.50 also ACDELCO
    the PCV-+GROMMET was about $7
    so actual cost about $100-just $43.30 "needed"
    but the wires are at least 10 years old-plugs also
     

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