98 suburuban hiccups at highway speeds

Discussion in 'Chevy C/K Truck Forum' started by mjh46560, Feb 22, 2014.

  1. mjh46560

    mjh46560 New Member

    Important safety tip to do it with the engine off!! I don't like leaning over the running fan anyway. I thought that since the truck had a TPS it was all electronically controlled not cable controlled like the old carborated engines.
  2. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    Nope it has a cable GM didnt get that advanced on their V8s until 2004. The TPS is need because it has a cable so the computer can see what the throttle is at.
  3. mjh46560

    mjh46560 New Member

    Ok, I haven't looked that closely at it yet. The wife is using it to get girl scout cookies for next few weeks. My garage is no longer my man cave, but it does smell good!

    Where is the TPS located at?

    Thanks for all the help and suggestions.
  4. Scott_Anderson

    Scott_Anderson Rockstar 100 Posts

    Locate the throttle cable connection, the TPS will be on the opposite end of the shaft that the cable connects too.
  5. cmoreno302

    cmoreno302 New Member

    My '96 c1500 does something similar. Once it's at the highest gear @ cruising speed, it hesitates and it almost feels jerky. I have to either give it more gas or let go and give it gas again to make it get out or that retardation or hesitation it has. I once pulled the distributor out without knowing to mark it. It ran ugly. Took it to a shop and they reĆ­ stalled it. Not sure if it's a timing issue or what.
  6. cmoreno302

    cmoreno302 New Member

    Also also if I'm idling on a uphill. Once I take off it hesitates as if it had power loss.
  7. mjh46560

    mjh46560 New Member

    I finally got around to replacing the TPS. It was very easy and quick to do, but cost $60 for the part. I took it out for a week long trip over spring break, highway driving and it still has that little hesitation. I am wondering if doing a seafoam treatment or taking it in to a shop and doing an injector check and clean would be beneficial? I have never used seafoam, but read a lot of positive comments on here about it. Anyone have any input?
  8. mjh46560

    mjh46560 New Member

    After doing several tanks of injector cleaning with no help, I talked to a local GM mechanic that has his own shop. Said that hesitation sounds electrical then asked when I did the last tune up. I looked at my logbook and after 114K miles my 16 year old 'burb had never been tuned up. He did it, new plugs, wires, rotor, cap, PCV and a few other items. Now it runs like new and no more little hiccup at highway speeds. Why didn't I think of that months ago? Its those damn simple things that cause the problems.
  9. Fe Fanatic

    Fe Fanatic New Member

    Do not rule out the ignition system. Look at the rotor, they have been known to allow spark through their center to ground. It will get progressively worse over time to the point it will quit altogether. Also the coil wire and spark plug wires can be the culprit. It only takes one wiring allowing spark to go to ground intermittently to give you those same symptoms. If your spark plug wires are over 5 years old I would suspect them.

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