Lurching/hesitation at high speeds

Discussion in 'Maintenance/Repair' started by Maxtanner1, Aug 3, 2015.

  1. Maxtanner1

    Maxtanner1 Newbie

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    Hello, I've got a 1980 long bed pickup with the 3-speed automatic transmission. It's had a weber 32/36 professionally installed recently along with new plugs, plug wires, distributor, and vacuum advance. Worth noting is I never had THIS particular issue with the stock carb. In town it runs just fine, accelerates through the gears, purrs, runs like new. However, now when I get on the highway it's sort of hit or miss (happens 75% going uphill, otherwise it will do it once in a while on flat surfaces) but it will start losing power, bucking and spurting, refusing to accelerate and backfiring. If I pull off to the side of the highway and start it up again it will act just fine after an episode. I'll go from a steady 75MPH down to 60 all while the truck lurches in a back and forth motion. Has a full tank but exhibits the symptoms of running out of gas or a misfire. Other times it will make 200 mile trips over mountain passes without any signs. Do I need a fuel regulator or a new pump? Just trying to get my bases covered before I go she'll out money.
     
    Last edited: Aug 3, 2015
  2. White Trash

    White Trash Toyotaholic

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    You're running out of fuel due to the jetting being too lean.
     
  3. Maxtanner1

    Maxtanner1 Newbie

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    Is this a common problem with the weber on these trucks? Does it need to be rejetted or just tuned via set screw? My mechanic suggested it could be 35 year old fuel lines or the factory pump starting to fail.
     
  4. tacobo670

    tacobo670 Addict

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    my buddy had the same issues. would drive fine, but on hills or under heavy load/acceleration, it would wig-out like it wants to die. sputters and misfires. also running a 32/36. rejet to a little bigger. now u can stomp on it all day no issues.
    its sounds like its running lean. plus, not a bad idea to just replace pump and lines.
     
  5. Maxtanner1

    Maxtanner1 Newbie

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    Also it's 2WD. Yeah the it would probably be worth doing all of that. It's just weird cause I can stomp on it in town and it goes goes goes with no hesitation or issues of any kind, it just appears at high speed cruising or up hills on the freeway. Could this be a timing/vacuum advance issue as well? I will probably just do another tune up as well.[​IMG][/url][/IMG]
     
    Last edited: Aug 6, 2015

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