1987 Chevy Truck Stumbling Over Itself

Discussion in 'GM Powertrain' started by 4x4_only, Aug 8, 2008.

  1. 4x4_only

    4x4_only Member

    Hey all,

    I have an 87 Chevy 4x4 that I've been fixing up over the past few years. It has 5.7/350, 700R4 Tranny, and currently has a 12" lift and Dana 60's. Anyways, it's run great over the past year but yesterday I drove it to work up in the hills and it finally decided not to get along. Here's what happened.

    I was driving to work and I was noticing that when I'd pedal down, the truck did not seem as responsive as it normally does. TO see what was up, I floored it to pass a semi but the truck never really got up and went, hardly went into the passing gear. Almost at work I was heading up a decent grade and even though I was standing on the throttle, i was slowing down up the hill. Half way up the hill I downshifted to get the rev's up and the truck made it up the grade fine but revvin' like hell. I get to the top of the hill and shift back up into four speed but when I pull into work I notice the truck is idle-ing very rough, and the breaks didn't want to catch.

    I drove it around the parking lot during lunch and it had a really bad hesitation at low idle, breaks were weak, and when I'd hit the gas, it was like it was stumbling over itself. Even after it would smooth out, it still felt unresponsive to the pedal. I managed to get it home and checked all the vacuum lines for cracks but they were all good.

    Any Ideas on what I should check next? Anybody had anything like this happen to them? Like I said, truck ran great until the other morning.

  2. GaryL

    GaryL Epic Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Welcome to the site.

    Pull the plugs and see how they look. They should be a nice tan color. If they are not, see if you can post a picture of them to give us an idea as to what happening.

    How long since your last tune up? Is it carbed or tbi? Is the engine revving and not pulling (transmission slip) or is it just sluggish?
  3. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    distributer cracked inside and not getting a good spark/contact to the wires and plugs, this is almost the exact same symtoms when it happened on my 99 burban
  4. 4x4_only

    4x4_only Member

    Thanks for the welcome.

    The plugs were acturally replaced about two months ago and still look good. The last official tune up was done a little over a year ago the last time I smogged it and everything (so i was told) checked out fine. The motor is a newer crate motor (stock replacement) that only has about 20,000 miles on it. And no it doesn't feel like a tranny slip, when the motor revs up the truck shifts and goes fine...it's just sluggish at lower idles and it spits and sputters a little.

    I'll check out the distributor see how it looks. Vncj96 did you go with an aftermarket distributor from say MSD or did you just do a stock replacement? I was thinking about a cam & intake swap so i guess if it had to go now it's almost "good" timing.

    If it's not the distributor, any other ideas?
  5. Crawdaddy

    Crawdaddy All hail the Mad King!! Staff Member 5+ Years 1000 Posts Platinum Contributor

    double-check your plug wires. Sounds like what happened when I lost 2 cylinders and the death of my transmission soon followed. Check the oil, make sure you have plenty still. Check the transmission fluid. The transmission could be causing enough strain to make the motor lug down.
  6. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    I just did a "factory" tuneup until i truly decide what to do with my baby, hoping for a custom tune and upgrade plugs, wires and distributer
  7. black jack

    black jack Rockstar 100 Posts

    im just thinking you say you checked the wires , plugs and cap. hows the fuel getting plenty. maybe you got bad fuel, fuel filter. try cleaning out the throttle body. maybe its gummed up. does the engine service light come on. could be a sensor. i had a 95 camero that the car would go great til all of a sudden it hesitated and shut off . pretty scary doing 70miles an hour but it was the cam sensor. also hows the timing. just trying to think of some possiblitys it could be and problems i had in past that was sim. situation. i know it sounds like a plug or wire or even the cap but cant rule out possiblitys.
  8. 4x4_only

    4x4_only Member

    Check engine light doesn't come on.

    I'm going to change the fuel filter, plugs, and wires sometime this week and we'll see how she runs. I'll also try cleaning out the throttle body and see how we run by the end of the week.
  9. burbanguy

    burbanguy Rockstar

    Any luck yet?
  10. Maximous

    Maximous Rockstar

    i dont know about your year model, but i had problems like that with some of my older vehicles, try turning full lock, engine idleing and brakes on, so basically drive normal to an intersection, get kinda heavy on the brakes and turn, not at a great speed either as that could be dangerous, see if the truck cuts off, or gets near it, if so, i would have someone check your vaccuum system, ive had alot of problems with GM vacuum, maybe just me though

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