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  1. #1

    Default 94 GMC Sonoma Help

    Hey guys so my Co worker has a 94 GMC sonoma with 156K and hes asking a grand, that said there is somthing going wrong with it he said one day it like bogged out on him he could barely accelerate, but then he went to move it like a week later and it seemed fine.... do they start getting problems? if so what kind? and it had the 4.7L v6 he said he just replaced the EGR valve. im not really familiar with GMC vehicles so anything helps.

    thanks guys.

  2. #2

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    Quote Originally Posted by kwag415 View Post
    Hey guys so my Co worker has a 94 GMC sonoma with 156K and hes asking a grand, that said there is somthing going wrong with it he said one day it like bogged out on him he could barely accelerate, but then he went to move it like a week later and it seemed fine.... do they start getting problems? if so what kind? and it had the 4.7L v6 he said he just replaced the EGR valve. im not really familiar with GMC vehicles so anything helps.

    thanks guys.
    That's a really good price, especially considering that it's probably an easy fix...especially if you do it yourself, and most of the time with GM trucks, you can.

    Here's my guess, it's a fuel pump going out...could also be time for new plugs and wires...

    If you check with the dealer, http://gmpartsonline.net, neither of those problems is costly.

    Losing power under acceleration is almost never an internal engine or transmission problem

  3. #3
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    TRPLXL2's Avatar
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    Welcome to the club!!!

    I would buy it for $1,000, would be a good work vehicle after you invest a couple hundred in it.
    2004 Chevy Colorado
    LS1 5.7 swap/TBSS rear axle swap

  4. #4

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    Exactly my thoughts. He just told me he thinks a cylinder is floating he looses power going up hills and stuff

  5. #5
    Sr. Apprentice Gramps43's Avatar
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    Kwag lets start with, it's a 4.3 Liter that might save some embarrassment when you ask a parts guy for a 4.7. Also cylinders don't float valves and boats do and valves won't float until you hit the top of the RPM range. Now that that is outa the way a grand is a good price if it is pretty rust free and free of major dings. If you get it first thing is to take it to a shop that can scan an OBD 1 system and get any codes that pop up. They will probably ding you between $30 and $50 to scan but then you will know what needs attention. Silverado mentioned the fuel pump, OBD 1 doesn't look at fuel pressure so get a pressure meter (they're not expensive) and check the pump pressure, both with and without the engine running. The pressure will depend on what kind of injection it has:

    Injection type / Key On / Engine Runng.
    TBI...................9>13....... 3>10
    MFI................ 41>47....... 3>10
    CMFI.............. 58>64 .......3>10
    CSEFI............. 55>61....... 3>10

    Good luck with it should you decide to get it, they are good little trucks.

    Gramps

  6. #6

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    Yeah 4.3 my badd lol. i think its rust free lol but it has no front bumper... and yeah i can probly do most work i have a 01 is300 that is a nightmare to work on... so if this is fairly easy it shouldent be a problem. know of any scanners that arnt too expensive that i can buy? ever herd of the PLX?
    ill probly just end up doing the fuel pump for **** and giggles along with plugs and all fluids.

  7. #7
    Master Mechanic BurbanMan's Avatar
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    Sounds like the cat converter is a good candidate for testing also. $1k is a good price. Pull the O2 sensor in front of the cat and see if it quits bogging. (Provided you can duplicate symptoms that is)

    Check engine light codes can be pulled by yourself using a paper clip. That will save you the $30-$50

    Plug both ends of the paper clip in to the two slots on the right on the top row. This plug can be found under the dash on the driver side.
    Chuckie!!!


  8. #8

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    Yeah he said it probly needs a new cat.. and i will try that. also i just use the paper clip? where do the codes show?
    Quote Originally Posted by BurbanMan View Post
    Sounds like the cat converter is a good candidate for testing also. $1k is a good price. Pull the O2 sensor in front of the cat and see if it quits bogging. (Provided you can duplicate symptoms that is)

    Check engine light codes can be pulled by yourself using a paper clip. That will save you the $30-$50

    Plug both ends of the paper clip in to the two slots on the right on the top row. This plug can be found under the dash on the driver side.

  9. #9
    Sr. Apprentice Gramps43's Avatar
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    The Sonoma should be a piece of cake compared to an is300. I have looked at both Amazon and ebay and they the full gamut from expensive!! to cheap. I saw one at Amazon for about $140 that will do both OBD 1 & 2 which would cover the is as well as the Sonoma. LMC truck has fuel pumps for around $70, Amazon has a test gauge (last page) with Schrader valve connector for Around $40. Plugs and fluids would be a good place to start.

    Y'all have a merry-merry and a happy-happy,
    Gramps

  10. #10
    Master Mechanic BurbanMan's Avatar
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    Quote Originally Posted by kwag415 View Post
    Yeah he said it probly needs a new cat.. and i will try that. also i just use the paper clip? where do the codes show?
    all you need is a paper clip. Once you plug it in, get comfy in the driver seat with pen and paper and turn the key to the on/run position without starting the engine Once that is done, the check engine light will begin flashing. I believe it will flash a code 15? Which is normal The way this works is, it will flash once and then flash 5 more times indicating 15. It will pause about 2-3 seconds in between each code.

    Here is a decent video.
    Chuckie!!!


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