Results 1 to 10 of 10
  1. #1
    OG Member Desertbound's Avatar
    Join Date
    Oct 2004
    Location
    Torrance / SLO, CA
    Age
    28
    Posts
    1,607

    Default 5.7L Chevy sputtering problem

    K, I know there's some Chevy experts on here and I'm getting very burnt out on working on mine. So, rebuilt the top end a few months ago, trucks been running great since. Changed out the Coolant temp sens, thermostat, and coolant, the other day, and all of a sudden, it runs like shit. Idles fine, nice and smooth. Temp is normal. Truck just sputters like mad once you start giving it gas. Backfires and misses like crazy, rpms shoot all over the place too. Feels like a fuel issue but Im not sure. Not saying the problem is related to me changing the coolant, im sure its not. All fuses are good, possible fuel relay issue?

    Ideas? Suggestions? Any sort of sensor to double check? Truck is a 1995 GMC K1500 w/ a 5.7L 117k miles. Thanks.

    -Rob
    Last edited by Desertbound; 04-21-2009 at 09:39 PM.

  2. #2
    Senior Member bmxking454's Avatar
    Join Date
    Apr 2008
    Location
    Pismo Beach
    Age
    27
    Posts
    1,216

    Default

    na-na KA-POW

  3. #3
    huge member rmprob's Avatar
    Join Date
    Apr 2009
    Location
    American Falls Idaho.
    Posts
    139

    Default

    Try unplugging the mass air, if it smooths out, that is your problem. That was the problem with my '03

  4. #4
    OG Member Desertbound's Avatar
    Join Date
    Oct 2004
    Location
    Torrance / SLO, CA
    Age
    28
    Posts
    1,607

    Default

    Do TBI motors even have a MAF sensor?

  5. #5
    gear installer mcdirt@1s1k's Avatar
    Join Date
    Oct 2007
    Location
    bakersfield ca
    Age
    30
    Posts
    7,481

    Default

    yes.
    Gear Installer







  6. #6
    Member
    Join Date
    May 2007
    Location
    camarillo
    Posts
    91

    Default

    had a 1996 camaro with lt1 do the exact same thing, replaced the fuel pump and that fixed the problem
    .

  7. #7
    Mega Member 3linkedchevy's Avatar
    Join Date
    Mar 2006
    Location
    Lake Forest,CA
    Age
    30
    Posts
    4,061

    Default

    Up to 95 there were no MAF on the TBI motors, MAF started in 96 with the VOrtec motors... start cheap, replace the fuel filter and check the pressure of the line

  8. #8
    Member mcarlson8's Avatar
    Join Date
    Dec 2007
    Location
    Kerman, CA
    Posts
    62

    Default

    Same thing just happened to my 96 although your isnt a vortec i changed my fuel filter, cleaned the air filter and cleaned my MAF with carb cleaner. Maybe clean your throttle body along with the air and fuel filter and see how it runs.

    Thanks,
    Mike

  9. #9
    Racer half-ass astronaut's Avatar
    Join Date
    Sep 2008
    Location
    El Segundo,CA
    Age
    30
    Posts
    8,645

    Default

    just remember on older motors, its alway air, fuel and spark, obviously 2 can be eliminated right here.


    i have a 91 GMC, and it had that same problem... came out on a very humid morning, and it wouldnt start. and i literally did exactly what you just did ( replaced temp sensor, thermostat, water pump, radiator and fluids a day before)

    check your distributor cap behind the air cleaner, take it apart(after you have labeled the plug wires of course), check the rotor for moisture and excess deposit on the contacts. might as well just replace the rotor and cap while you already have it taken apart ( $5 for rotor and like 15 for cap).

    it doesn't sound like a fuel problem, mostly because fuel pumps either work or they don't (most of the time)...

    if that doesnt work, start the engine, and look at the spray of gas on the injectors at idle, then twist the throttle open really quick, if you notice the injector spray at a faster rate, than your pump is still good, and its safe to say its an ignition problem.

    its a 5.7, its gonna be something real simple...
    "Someone who thinks logically provides nice contrast to the real world"
    "Takes more than a 40 of King Cobra and a little hippy cabbage to make a car that bad." <-- on the topic of Dodge/Chrysler
    Quote Originally Posted by sparkypyro View Post
    Fastest way to a million dollars in desert racing is to start with 2 million.

  10. #10
    Racer DiRt YoTa's Avatar
    Join Date
    Feb 2008
    Location
    Ram, Ca
    Posts
    7,180

    Default

    Coolant temp sensor sends fuel/air mix to the 'computer' and could be causing a stumble. Since that is the only sensor you replaced, I would put the old one back in, disconnect the battery-reconnect, then see how it runs...
    22RE Master Tech
    Got boost?
    "this is an 81 Honda... How dare you!"
    Quote Originally Posted by Kellen_Cox View Post
    Hooker travel is the bastard child of the offroad world. devide by 0 to get the true travel numbers.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. 1997 chevy s10 electrical problem.
    By motoxxxprerunnerranger in forum Truck Talk
    Replies: 18
    Last Post: 01-31-2009, 03:54 PM
  2. Doug Thorley headers chevy 88-98 2wd chevy
    By 951PRERUN in forum Parts & Accessories
    Replies: 5
    Last Post: 06-06-2006, 03:32 PM
  3. Sputtering Ranger, Missing, 94 4.0
    By Hollywood1 in forum Truck Talk
    Replies: 8
    Last Post: 11-16-2005, 08:34 AM
  4. sputtering?
    By schenie in forum Truck Talk
    Replies: 1
    Last Post: 05-04-2005, 05:41 PM
  5. Sputtering
    By Bink Designs in forum General Off-road Talk
    Replies: 3
    Last Post: 12-28-2004, 12:37 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •